Final Report Summary - SUSCLEAN (Sustainable Cleaning and Disinfection in Fresh-Cut Food Industries)
Executive Summary:
SUSCLEAN has as its strategic goal to contribute to the development and implementation of food product decontamination technologies and equipment sanitation conditions which are environment-friendly while ensuring food safety. The two key targets are the reduction or replacement of chlorine and the mitigation of the process water. For this purpose, the project has developed knowledge, methods and tools for the following activities:
- Characterization and the monitoring of the microbial contamination patterns
The sampling campaigns in large MPV industries showed that chlorine has a real effect on the level of product contamination and brings a significant protection against cross contamination from washing water. The colonization patterns of pathogenic E. coli O157 strains showed allelic variations in the general-stress response and survived significantly shorter on lettuce compared to strains showing wild-type sequences. The fresh-produce environment selects for stress-resistant strains that are subsequently a higher risk for public health. Viral pathogens (HAV) inactivation showed that the classical chlorine treatment and alternative chemical treatments as peracid formulation were not able to reduce by 4 log. Extension of predictive microbiology models/software and development of general risk assessment tool was proposed.
- Improving the hygienic design of equipment (geometry and surface)
E. coli did not grow into biofilms as on standard steel surfaces with hard diamond-like carbon coatings modified with oxygen (SICON) and the antimicrobial coating modified with Ag. Beneficial geometrical changes in terms of hygiene can be proposed for the washing tanks based on modelling using specific Computational Fluid Dynamics tools. New design options in pertinence with the European Hygienic Engineering and Design group induced longer periods before any significant growth of the biofilms in washing tanks at least over 24 h. A comprehensive document was written to list and detail the hygienic design requirements for the different part of the processing lines.
- Designing new decontamination approaches for fresh-cut food and sanitation strategies
The most promising methods were chosen amongst the following list on surface, water and products: phytochemicals, chlorine dioxide, ozone, hydrogen peroxide, organic acids, enzymes, copper suspension, pulsed UV light, pulsed electric fields, NEOW and ultrasound. NEOW was selected and tested at pilot plant scale with the advantage of on-site production, being less corrosive and effective at lower chlorine concentration. The organoleptic properties of the product, as well as the treatment impact on the salad shelf-life were not affected by the treatment. Potential benefits of using ultrasound technique to reduce the need for high chlorine concentration were identified at laboratory and pilot plant scale. Another promising approach is to use PEF (Pulsed Electric Field) together with a lower concentration of chlorine, which was tested at pilot-plant scale. Ozone and UV were selected together to treat water and it was possible to reach a water reduction up to 42% with lower water/lettuce ratio, keeping the same hygienic level of washing water. Additionally, a reduction in water consumption will be attained if a continuous dosing system is adopted whereby the same water can be efficiently used for 4 to 5 days.
- Proposing guidance and recommendations to renew the best available processing techniques (BAT); assessing the impact of sanitation and decontamination strategies in line with the Directive on Integrated Pollution Prevention Control (IPPC) 2008/1/CE;
Inventory analysis on water, chloride and energy consumption as well as wastewater production in disinfection and sanitation processes at a reference plant was carried out in collaboration with a company. Life cycle assessment was carried out for the above selected techniques for industrial or pilot plant scale testing. A sensitivity analysis was carried out to identify key parameters for the LCA in sanitation and decontamination processes.
Project Context and Objectives:
The market of ready-to-use minimally-processed vegetables (MPV) has grown rapidly over the recent decades. Chlorine has been widely used to decontaminate fruits and vegetables in the fresh-cut industry in order to reduce the load of microbial contamination. The association of chlorine with the possible formation of carcinogenic chlorinated compounds and the excessive water use prompted the European Commission to finance research into the development of alternative sustainable cleaning and disinfection methods.
The other challenge for the MPV industry is the minimization of water consumption and wastewater discharge rates which is considered as huge nowadays. More than 30 l per kg of products could be used in countries where the use of chemicals in the process is forbidden.
Hence some EU countries as in the Netherlands, Belgian and UK forbid its use for safety reasons. There is no common regulation throughout Europe on the use of chlorine for fresh-cut food processing. There are now discussions at the political level in countries like the Netherlands and Belgian on the possibility to accept the use of disinfectants as Chlorine in the fresh-cut food industries.
Food cross contamination could not be avoided during product washing operations with a view of water consumption reduction in conjunction with food production sustainability. The other issue is that some legislation in Europe demands an acceptable contamination threshold of the final product. In France the legislation impose less than 106 CFU per g of product which is impossible to achieve with no help of any chemicals in the washing systems.
SUSCLEAN advances are thus aimed at mitigating water and reduce or replace chlorine consumption whilst taking into account environmental and food quality impacts for the fresh-cut food industry to answer to the double challenge of less water and if possible no chlorine.
SUSCLEAN has as its strategic goal to contribute to the development and implementation of a new generation of equipment sanitation and food product decontamination technologies which are environment-friendly while ensuring food safety. Sanitation includes cleaning which is the action of removing all organic matter up to biofilms and disinfection which consists of decreasing the viable microbial population on food processing surfaces, with special attention paid to pathogens.
For this purpose, the project developed knowledge, methods and tools aimed to:
- characterize and monitor the microbial contamination patterns,
- improve the hygienic design of equipment for the fresh-cut product industry
- design new decontamination approaches for fresh-cut foods and sanitation strategies (cleaning and disinfection procedures) for their processing equipment along the supply chain;
- propose guidance and recommendations to renew the best available processing techniques (BAT); assess the impact of sanitation and decontamination strategies in line with the Directive on Integrated Pollution Prevention Control (IPPC) 2008/1/CE.
These scientific and technical advances will help to reduce the use of water and chemicals (noticeably chlorine), while ensuring food safety, sustainable practices and preserving food quality in the European fresh-cut food industry.
The project objectives could be detailed as follows:
At the scientific level,
- Determine the points of microbial food product contamination at the critical food processing stages;
- Understand colonization patterns of spoilage and pathogenic microorganisms at these points, both on food and processing equipment;
- Develop model colonization systems that can be used for sanitation and decontamination studies;
- Investigate sensitivity of microorganisms (essentially bacteria) to cleaning and disinfection procedures and identify any mechanisms developed by these microorganisms to resist disinfection procedures;
- Characterize the impact of new sanitizing and decontamination alternatives on pathogen virulence and infectivity;
- Characterize the role played by equipment geometry and materials – at the macro, micro, and nanometric scales – in microbial contamination patterns and persistence;
- Assess the environmental impact of existing and improved sanitation and decontamination treatments along the MPV supply chain;
- Develop of predictive models to consider the impact of microbial colonization of food processing surfaces on MPV colonization, in conjunction with applied sanitation and decontamination treatments;
- Develop microbiological testing protocols with the potential of detecting specific pathogenic microorganisms that may, by detecting any contamination within one hour, allow a quick positive release of MPV products.
At the technological level,
- Conceive, benchmark, and propose alternative sanitation treatments suited for equipment cleaning and disinfecting procedures along the MPV supply chain;
- Conceive, benchmark, and propose alternative chemical and physical MPV decontamination treatments;
- Optimize the use of chlorine in MPV decontamination;
- Design and test sanitation and decontamination operations aimed at tailoring the use of water;
- Establish guidelines to hygienically design equipment to ease the cleaning procedures;
- Evaluate impacts of alternative decontamination strategies on nutritional and sensory properties of MPV;
At the societal level,
- Renew the code of best MPV processing practices with respect to sanitation and decontamination;
- Issue recommendations to the EC;
- Transfer the gained knowledge to the European industry, in general, and to SMEs in particular.
Project Results:
Key result n°1: Microbial contamination and persistence
Workpackage: WP1 - Microbial contamination and persistence along the food chain
Research aims and background:
The market of ready-to-use minimally-processed vegetables (MPV), has grown rapidly over the recent decades. Chlorine has been widely used to decontaminate fruits and vegetables in the fresh-cut industry in order to reduce the load of microbial contamination. However, the association of chlorine with the possible formation of carcinogenic chlorinated compounds and the excessive water use prompted the European Commission to finance research into the development of alternative sustainable cleaning and disinfection methods. The development these alternative methods require a deeper understanding of the biodiversity and colonization pattern of pathogenic and non-pathogenic (i.e. spoilage) microorganisms. In addition, the efficiency of newly developed decontamination method should be evaluated for truly pathogenic microorganisms. Insights on the contaminations scheme of industrial sites and further understanding of microbial colonization patterns will be helpful in redefining quality systems and intervention strategies.
Results and applications:
Contamination levels of equipment surfaces was found to be high but variable (0.7 to 10.5 log10 CFU/sample). Washing in product in water with chlorine reduced the microbial load significantly compared with washing in only water but at the end of shelf-life (which was longer for the product washed in chlorinated water) was the same. Many of the bacterial isolates obtained from the processing facility were able to grow and form biofilms in the laboratory at temperatures as low as 10 degrees Celcius and some of these were found to be highly resistance to chlorine. Laboratory experiments were conducted to study the survival of highly pathogenic E. coli (EHEC) on cut lettuce. It was observed that survival was strain dependent, ranging from no decline to 2 log decline over 3 weeks. We identified a suitable genetic marker for survival: the general stress response gene rpoS. Strains with a wild-type rpoS gene were significantly better survivors. In addition, these strains were higher resistance to an acid shock mimicking the human gastric barrier. This indicates that the presence of EHEC in this environment selects for stress resistant strains which form an increased public health risk. Washing product contaminated with EHEC in chlorinated water and electrolyzed water as an alternative model reduced the pathogen by on average 2.5 log, which is one log more as with only water. However, large strain variation was observed. With respect to the inactivation of Hepatitis A virus, the classical chlorine treatment as well as alternative peracid formulations were not able to reduce the recommended 4 log reduction (maximum reduction was 1.5 log). Biofilm growth of non-pathogenic (spoilage) bacteria can be prevented by 30 ppm of chlorine when the biocide is present from the first stage of the biofilm initiation. However, once settled and spatially organized, and as observed in different industries, biofilms are very difficult to eradicate. Finally, a risk assessment tool was developed by which the industry can assess and optimize the use of disinfectants in their processes regarding the inactivation of microbes given a number of parameters (i.e. concentrations, pH, temperature).
Significance and benefits:
Our results showed that microbial contamination in the vegetable industry can be high, but most of this are spoilage organisms. The addition of a disinfectants to the washing water will prevent cross-contamination and will prevent biofilm growth on equipment. However, already established biofilms are extremely difficult to remove. In addition, biofilms formed by non-pathogenic bacteria can trap pathogens which are subsequently protected by sanitation actions. Finally, food safety interventions taking by the industry should not be focused on the actual removal of pathogens from the product since the efficiency is limited and highly variable. In the end, the prevention of contamination during primary production in the field remains the most important factor with respect to fresh produce safety.
Successful applications:
As a spin-off of the SUSCLEAN a project was started financed by the fresh-cut produce industry to construct a risk assessment model that assesses the public health relevance of cross-contamination in the washing step of fresh-cut produce processing. In some EU member states, like The Netherlands, the use of disinfectants in the water is prohibited. However, the industry in these countries apply force to the government to allow the use of disinfectants in the washing water. The main argument is to prevent cross-contamination by pathogens and thereby provide an intervention to possible outbreaks. However, we showed that the public health relevance of cross-contamination very limited and only relevant in extreme (i.e. unlikely) contamination events. Together with the experimental results of SUSCLEAN showing a limited efficiency with respect to pathogen removal this questions the necessity of using disinfectants in the washing water. However, in the situation like in The Netherlands, the quality of the water relies on continuous addition and refreshments of washing baths with large amounts of potable water to minimize the event of accumulation of micro-organisms in the water and transfer of micro-organisms from the water to the product. This prompts the necessity to study the balance between food safety and sustainability in terms of water and energy use. This should be focus of future projects in this area.
References
A very successful workshop entitled “less water and no chlorine: is it a dream?” was held in Wageningen (The Netherlands) on December 4th. The results of three European projects dealing with a similar topic were presented (Vegitrade, Resfood and Susclean), followed by an afternoon of mediated discussion with people from industry, science and policy.
Several scientific papers are in preparation on:
1. Microbial contamination along the production line of a large-scale fresh-produce processing facility.
2. High-throughput real time assessment of biofilm formation of isolates obtained from machinery and products of large-scale scale fresh-produce processing facility.
3. Survival of pathogenic E. coli and Hepatitis A on lettuce and resistance to disinfectants.
Key result n°2: Hygienic design evaluation: new surface alteration to prevent food product cross contamination and reduce environmental impact of processing and cleaning operations in the fresh-cut food industry
Workpackage: WP2 - Design of equipment to mitigate microbial contamination and persistence
Research aims and background:
In pursuit of the reduction of the consumption of water and chlorine in minimal processing fruit and vegetables (MPV) productions, food companies are potentially facing increasing microbial risks due to bio-film formation on food production surfaces, transfer of contamination to the product and/or inadequate decontamination of MPV products.
Hence surface properties are known to impact adhesion of bacteria and the subsequent growth of biofilms.
Different strategies to mitigate product contamination during the washing of produce could be proposed as:
- increasing bacterial adhesion on tank surfaces to lower the bacterial concentration in the washing liquor,
- avoiding bacterial adhesion to reduce the potential formation of biofilms,
- lowering the attachment strength of the bio contamination to enhance the ease of cleaning.
The washing tanks are not exclusively concerned and this could be expanded towards the other equipment in the fresh-cut processing lines as chopping machines, conveyor belts, packaging machines, etc.
Results and applications:
Key parameters of the micro and nano surface topography and of the surface energy were identified based on their consequences on microbial adhesion and biofilm development.
Different types of stainless steel surface coatings were studied such as hard diamond-like carbon (DLC, a-C:H) coatings modified with silicon and oxygen (a-C:H:Si and a-C:H:Si:O called SICAN and SICON), Fluorine DLC and antimicrobial coatings prepared by sputter techniques as Silver (Ag), Ag modified a-C:H (a-C:H:Ag) and titanium dioxide TiO2 known to have photocatalytic properties.
Analytic investigation concerning the deterioration behaviour of the coatings were considered. Here methods like Infrared (IR) spectroscopy, SIMS (Secondary Ion Mass Spectrometry) and contact angle measurements were applied. Especially for the modified DLC coatings an increase of the surface energies was revealed after exposure with acids and hydroxides. The main reason for this behaviour was a clear increase of the polar component of the surface free energy.
Surface energies were found to be affected by the presence of organic/chemical compounds found in the detergent, water and the washing liquor. Such surface conditioning was found to reduce differences in the surface energy of the different coatings proposed. However a quite large range of surface energies was tested from 31 mJ/m² (Fluorine DLC) to 50 mJ/m² (2B finished AISI 316 stainless steel electropolished) combined with three average surface roughness from 1 m (microbeaded statinless steel), 0.3 (Standard 2B AISI stainless steel) and 0.1 m for the other options tested.
No beneficial effects were found in washing tanks in terms of reduction of the microbial trapping and on the subsequent biofilm growth with Pseudomonas species. Laboratory experiments with Escherichia coli showed similar results as no impact on the bacterial adhesion was detected but SICON and the silver-DLC coatings were found to reduce the biofilm growth for different reasons.
Product hold-up effect was studied with some of these surfaces. The objective was to evidence any beneficial effect of the surface properties on the attachment of i.e. salad leaves to the surfaces. Some interesting effects were found regarding the reduction of product holdup as too smooth surfaces or hydrophobic ones induce significantly product attachment. Wet produce as demonstrated with salad leaves deeply enhance the attachment on surfaces.
Significance and benefits:
Even if this study highlights the need of additional work to be able to define precisely the areas of applicability of surface coatings, the strategy of surface properties alteration remain definitely a key to the future. Commonly used sanitizing methods were shown to negatively affect the performance of the new surfaces which is a major drawback in their application to current industrial processes.
Any improvement in the reduction of the environmental impact of food processing would emerge from an integrated approach including surface alteration, equipment geometries and processing and sanitizing conditions.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.2 – Hygienic design recommendation and significance (2014)
Key result n°3: Hygienic design principles a way to prevent food product cross contamination and reduce environmental impact of processing and cleaning operations in the fresh-cut food industry
Workpackage: WP2 - Design of equipment to mitigate microbial contamination and persistence
Research aims and background:
The fresh-cut, minimally processed fruit and vegetable (MPV) market is of increasing importance to the food sector with dramatic growth having been observed in recent years, FAO (2010). This growth is thought to have been stimulated by the increased knowledge of consumers about the role of fruit and vegetables in a healthy diet coupled with a consumer need for convenience.
Food safety is not negotiable and within the global strategy to avoid any outbreak related to fresh cut food, hygienically designed machineries involved in the processing and packaging of such products appeared to be mandatory.
The related objective is that any change in the product washing and equipment cleaning operations towards a significant mitigation of the environmental impact due to the consumption of water and chemicals is jeopardized by machineries not hygienically designed. This is unfortunately the case for the equipment widely used in this food sector.
Background information on hygienic design can be found in sources including:
• Machinery Directive 2006/42/EC (formerly 98/37/EC)
• EN 1672-2:1997: 2005+A1: 2009 Food processing machinery-Safety and hygiene requirements-Basic concepts-Part 2; Hygiene requirements.
• ISO 14159:2002 Safety of machinery -- Hygiene requirements for the design of machinery.
• Publications of the European Hygienic Engineering Design Group www.ehedg.org.
• Publications of the 3-A association in the USA www.3-a.org.
• Publications of the National Sanitation Foundation in the USA www.nsf.org.
• Regulation (EC) 2023/2006 on good manufacturing practice for materials and articles intended to come into contact with food.
Results and applications:
A comprehensive guideline document was produced to document hygienic design best practice in the minimally processed fresh cut fruit and vegetables sector including cantaloupe processing.
It addresses the need to understand critical hygienic design factors in 4 main areas:
1. The speed of produce transit through washing systems
2. Equipment design to minimise product hold up and thus minimise washing times
3. Equipment design features that make it difficult to clean and would extend cleaning time/chemical use
4. Poor hygienic design features which are un-cleanable and could harbour microorganisms.
Equipment manufacturers are required according to the Machinery Directive to state the intended use of the equipment. When designing the equipment, manufacturers should also identify all the hazards associated with its intended use and undertake a risk assessment to design the equipment to eliminate hazards where possible. If the hazard cannot be eliminated through design then effective cleaning and disinfection instructions should be provided otherwise, additional information is required.
This information could include, for example: further monitoring, cleaning and disassembly instructions; specific processing conditions such as temperature controlled environments; limitations on the types of products that can be safely processed; and the requirements for any safety features to protect the operative.
Guidelines proposed by the Susclean project are strongly recommended as the available background information does not include the specific requirements for the fresh-cut food sector (vegetables and fruits). Data from the research activities of WP2 are available to strengthen the recommendations listed in these guidelines. The document focus is however broader than the washing tanks and address all the equipment and machineries involved in the fresh-cut food processing lines.
Significance and benefits:
These guidelines appeared as a new reference for this industry sector and should be a base for fresh product manufacturers to discuss and negotiate with equipment manufacturers.
Such guidelines document will be available for the industry and additional works are needed to have this document accepted by the EHEDG through the setting up of a working group of stakeholders to have these guidelines accepted and written under the EHEDG format. Anyway the partners involved in this work are members of the EHEDG and could be eligible to participate to the mentioned working group.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN 2.4 – Hygienic design principles (2014)
Key result n°4: Hygienic design evaluation of washing tanks: setting up a strategy to prevent food product cross contamination and reduce environmental impact of processing and cleaning operations in the fresh-cut food industry
Workpackage: WP2 - Design of equipment to mitigate microbial contamination and persistence
Research aims and background:
The reduction of the consumption of water and chlorine in fresh-cut food processing, industrials are potentially facing a microbial risk due to biofilm formation on technical surfaces impairing hygiene monitoring on the production site. Hygienic design principles are frequently not implemented in in-use equipment and machineries in the fresh-cut food industries.
A characterization at different scales of the influence of the design on biofilm development and resistance against cleaning operations was carried out. The foreground related to the mechanisms involved in biofilm installation and resistance was generated through studying the respective roles of the flow conditions, the presence or not of chemicals and kinetics of bacterial adhesion, biofilm development and biofilm removal.
Results and applications:
The criticality of the design was found to depend on three factors, the significance of the surface contamination, the biofilm growth kinetics’ shapes and the subsequent resistance to cleaning.
A strong beneficial effect of the proposed equipment geometry changes was observed:
- in the reduction of the microbial contamination trapping over the first few hours,
- with more than 8 hours delay in the biofilm development,
- in the biofilm structures observed and related to the hydrodynamics,
- In the subsequent resistance to cleaning.
The reduction of the microbial trapping is largely induced by the geometry modifications as open angles (over 100°) modifying the flow pattern with an increase in the wall shear stress (flow mechanical action). Moreover the biofilm growth kinetics were modified showing a lag phase which could cover more than 24 hours. Considering the processing time before any sanitation actions (8 hours as a whole day production), no significant bacterial growth could be seen allowing milder sanitation conditions (less chemicals and less water).
Splash areas were shown to be covered by three dimensional and dense biofilm structures. Hence, biofilms on surfaces strongly affected by the flow turbulences or located in protected areas against the flow shown very different structures. In protected areas, biofilms can grow in three dimensions with visible exopolymeric excreted substances and appeared to be significantly less dense that the ones impacted by the fluid motion (turbulences or splash zones) developing flat two dimensional structures.
The resistance to cleaning was found to be dependent on the biofouling structures. The most fragile biofilms against foam cleaning were those formed on vertical surfaces included the splash areas probably emphasized by any sliding of the foam during the cleaning process. The most resistant biofilms against foam cleaning were those formed on horizontal surfaces and/or grown in static conditions. Conversely the later appeared to be easily removed if cleaning includes chemicals and a mechanical action not always possible according to the machinery designs.
Enzymes were found to affect bacteria cells removal from surfaces by acting on the expolymeric substances present in the biofilms. No effect on the bacteria viability could be stated. A beneficial effect comparing to standard foam cleaning with chemicals was observed with biofilms grown in static conditions probably due the specific action of enzymes on the exopolymeric substances in the biofilm structure.
Depending on the areas concerned mechanical action (sanitation fluid flow) or not (foam cleaning and mild rinsing) could be carried out to get rid of the surface contamination. Anyway, aiming at reducing the criticality of washing tanks is also a question of compromises.
Flow modelling using specific Computational Fluid Dynamics tools was found to be useful to propose beneficial geometrical changes e.g. to avoid/reduce areas that are not or poorly accessible for the detergent i.e. forbidding any mechanical action, which are prone to be dead areas during the washing process.
Significance and benefits:
It can be thus stated that the risk of food cross contamination from the equipment surfaces is significantly reduced with the new geometries. Sanitizing strategies could be re-evaluated towards a higher efficiency while mitigating the environmental impact of such operations.
It is important to notice that the geometry improvements proposed in this work are in coherence with the European Hygienic Engineering and Design Group (www.ehedg.org) recommendations. This foundation is producing guidelines largely implemented in international and European standards and in the European legislation. The novelty here is the quantification of the consequences of the design improvement in terms of hygiene. Data obtained here are relevant to be used in risk analysis processes.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.2 – Hygienic design recommendation and significance (2014)
Key result n°5: Treatment of stainless steel equipment - Removal of biofilms with ultrasound
Workpackage: WP3 - Alternative equipment sanitising and MPV decontamination strategies
Research aims and background:
Ultrasound waves in liquids (e.g. in water) causes pressure variations which leads to cavitation. The implosion of the cavitation bubbles and the arising micro jets lead to a high local shear stress, which can remove cells from surfaces or even disrupt cell walls or membranes. Ultrasound waves in a frequency range of 20-100 kHz was used in several studies successfully for the deactivation of bacteria and cleaning of membrane fouling. For the decontamination of produce the use of ultrasound is limited, because of the heat development when sonication is used continuously. Nevertheless cleaning of stainless steel equipment with ultrasounds seems to be a promising alternative treatment for biofilm removal.
Results and applications:
To find the best working parameters a coupon with a biofilm layer in a saline solution was sonicated with different power settings for different durations with a 20 kHz sonotrode. At 50 % sonication power the killing and removal of the bacteria was inefficient, even after 5 minutes of sonication. At 100 % sonication power and a duration of 3 minutes the biofilm was completely removed from the stainless steel coupon. These results pointed out that the complete removal of biofilms with a 20 kHz sonotrode is possible. Another observation was that the sonication of the coupon additionally lowers the amount of microbial contaminations about 80 % in the surrounding liquid. An additional chemical agent could prevent cross contamination of the last 20 % of residual bacteria. All in all the treatment of equipment with ultrasound exhibit good results in laboratory scale experiments.
Significance and benefits:
An important advantage of ultrasound is that mechanical removal of biofilms is better than killing of the microorganisms with chemicals. Dead biomass is a possible starting point and anchor for new attachment and growth of microorganisms, because the dead cell mass is a nutrient donor for new populations to grow. Only mechanical removal can delay the biofilm formation.
Successful applications:
Cleaning of stainless steel surfaces in laboratory scale works successfully, but it is not possible to clean a complete industrial plant. Therefore the next step is to identify the critical zones, like dead zones etc., for the design a customised sonotrode.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.1 – Specification of applicable methods (2013).
SUSCLEAN D3.2 – Impact of alternative techniques on hygiene (2014).
Key result n°6: NEOW – an alternative to conventional sodium hypochlorite to prevent cross contamination in MPV industries
Workpackage: WP3 - Alternative equipment sanitising and MPV decontamination strategies
Research aims and background:
Electrolyzed Oxidizing Water (EOW) is obtained by an electro dialysis of a diluted salt solution. At the anode side an acid solution consisting of oxygen and chlorine gas, hypochlorite ions, hypochlorous and hydrochloric acid, and at the cathode side a basic solution consisting of hydrogen gas and sodium hydroxide accrues. To obtain the Neutral Electrolyzed Oxidizing Water (NEOW) the formed acid and basic solutions are mixed. This leads to a solution with is expected to be less corrosive and irritating. The big advantage of NEOW compared to sodium hypochlorite (NaOCl), which is typically used for the decontamination of minimally processed vegetables (MPV), is the on-site production. The effective component in both solutions is the hypochlorite ion, which penetrates the cell wall of bacteria and disrupts the membrane transport proteins resulted in a disrupted energy production. Because of further compounds in the NEOW like hydrochloric acid and sodium hydroxide a lower concentration of NEOW has the same decontaminating effect as conventional applied sodium hypochlorite.
Results and applications:
Washing of MPV (salad) with NEOW was compared to NaOCl and water. An unexpected result was that even the cleaning with NaOCl is not more effective than purging with water. This leads to the assumption that NaOCl is not decontaminating the salad in particular, but prevents cross contamination in the food processing industries. This discovery foregrounded the disinfection of the washing water, for which NaOCl is typically used at a content of free chlorine from 60 ppm to 90 ppm in MPV processing. The experiments of WP 3 and WP 4 (details see in D3.2 and D 4.2) pointed out that a similar reduction of contaminations in water can be achieved with NEOW at lower levels of free chlorine (29 ppm).
Significance and benefits:
The biggest benefit is the on-site production of NEOW with a generator and a diluted saline solution. For the experiments at laboratory scale a suitcase NEOW generator was constructed. At industrial stage a pilot plant was installed at Vitacress (see also key result of WP4: Optimizing cleaning and disinfection processes to reduce the use of water and chlorine, or D 4.3). The use of NEOW at lower levels of free chlorine is another big benefit.
Successful applications:
The NEOW technology was applied in a salad producing industrial side for large scale experiments. The results were very promising with respect to decontamination and product quality.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.1 – Specification of applicable methods (2013).
SUSCLEAN D3.2 – Impact of alternative techniques on hygiene (2014).
Key result n°7: Reduction of the water consumption: washing water reuse after O3/UV treatment
Workpackage: WP4 – Optimising cleaning and disinfection processes to reduce the use of water and chlorine
Research aims and background:
The MPV washing step was identified as a key process step where water consumption can be reduced, by minimizing water addition to the washing tank and increasing the process water useful life. To achieve this, treatment in closed loop to prevent MPV cross contamination was proposed.
Ozone is one of the most powerful common oxidizing agents and its decomposition leaves no residues. O3 is very effective in destroying microorganisms by the progressive oxidation of vital cell components, preventing microbial growth, either in Gram+ and Gram – bacteria, as well as spores and vegetative cells. A set of experiments were conducted at laboratory scale to get an estimation about the dose of O3 and the O3-water contact time, needed to reach an effective removal of the contaminants previously detected in the washing industrial water (micro-organisms and pesticides).The methodology followed is shown in the attached pdf figure 1: General methodology to validate the use of O3 and O3+UV as water regeneration treatment.
Mesophiliic bacteria (5.9x106 cfu/mL) and ortophenilphenol (5 ppb) were added to the industrial washing water. Almost total removal of microorganisms (6 log reduction) and pesticides was obtained using 0.06 g O3 and UV dose of 60 mj/cm2 during 2.5 min of duration treatment. Subsequently, this treatment was tested at semi-industrial application (pilot plant scale).
Results and applications:
In order to assess the effectiveness of the washing water treatment proposed (O3/UV), a set of pilot plant trials were carried out to scale down the corresponding industrial washing process. A washing machine pilot plant GWB-100 was employed (volume of 220 L of water, capacity for washing 100 kg vegetable/h) and 220kg of vegetable were washed. An ozone and UV irradiation system was designed and built to treat water in a closed loop.
The ozone system used in the experiments consists of an ozone water reactor (10 L) where a stream of the washing water was pumped in for its treatment with ozone. The ozone was generated with an ozone generator (10 g/h) fed with air coming from the oxygen supply system. In order to avoid vegetables alteration due to their contact with ozone, an UV lamp was placed to remove the residual O3 presents into the treated water.
See in the attached pdf figure 2a and 2b with the scheme of the pilot plant built to conduct the experiments.
A reduction of 20 % in water consumption was reached when O3/UV was used and the addition of fresh water was completely eliminated. For the chemical oxygen demand (COD) a reduction of 55% was reached. These results were obtained when the same washing ratio of water:vegetable (L/kg) were kept in both experiments and similar to the washing industrial ratio.
Using a water:vegetable ratio of 2 L/kg (smaller than the typical industrial ratio 6.37 L/kg), led to similar results of the O3/UV treatment, even when the hygienic conditions were worse. A reduction in water consumption of about 42 % was reached, while the levels of microorganisms were maintained and the pesticide content reduced (< 50 %) in the washing tank. Furthermore, the chemical oxygen demand (COD) was reduced to 35 % in the generated waste water.
Significance and benefits:
The effectiveness of the utilization of ozone/UV in the first washing step to treat the water in a closed loop has been demonstrated in a pilot plant scale. Significant high benefits are expected in water consumption reduction (20-42 %) and COD reduction (35 -55%), in industrial application.
Successful applications:
For the first industrial application, a study of the economical viability should be carried out. After scaling up the O3/UV system and after adjusting the parameters involved in the effectiveness of the industrial treatment (flow rate stream treated, dose of O3, contact time) a complete validation process should also be developed. Furthermore additional investigation should be developed to assess the effectiveness of the O3/UV treatment in other washing processes, i.e.: fruits.
References:
Susclean Deliverables 4.1 4.2 and 4.3.
Key result n°8: Optimizing cleaning and disinfection processes to reduce the use of water and chlorine – Water disinfection
Workpackage: WP4 – Optimising cleaning and disinfection processes to reduce the use of water and chlorine
Research aims and background:
The main objectives were: (i) to install NEOW technology at an industrial site of salad processing; (ii) to measure and validate NEOW as water disinfectant and its effect in water quality; (iii) to compare NEOW suitability as an alternative to sodium hypochlorite concerning water disinfection to wash salads reducing the free chlorine concentration; (iii) to compare organoleptic properties of salad washed with NEOW over the product shelf. In order to evaluate the water quality after treatment with NEOW, samples were collected at Vitacress from the washing and sanitizing tanks. The microbial load reduction and population in water after chlorine from NaOCl (from 60 to 90 ppm) and NEOW (29 and 40 ppm) was quantified and characterized.
Neutral Electrolyzed Oxidizing Water (NEOW) was obtained by electro dialysis of a diluted salt solution. This electro dialysis results in two components: at the anode side, an acid solution consisting of oxygen gas, chlorine gas, hypochlorite ion, hypochlorous acid and hydrochloric acid; at the cathode side, a basic solution consisting of hydrogen gas and sodium hydroxide.
The mixture of both solutions results in a neutral solution with bactericidal effect with high oxidation-reduction potential, chlorine being released in a more stable state. Due to this fact, the free chlorine concentration from NEOW needed to achieve the same microbial reduction is less to the one applied when traditional NaOCl solutions are used.
The production and laboratorial application of NEOW have been described in previous Deliverables (D3.1 and D3.2). This product was selected as a promising alternative technology to be tested at larger scales (pilot-plant and industrial plant). Some tests were made at laboratorial scale to find optimal solutions for the application of NEOW, alone or together with the traditional chorine addition method (described in D4.2). The industrial partner Vitacress selected NEOW for trials at the production plant.
Results and applications:
Overall, Streptococcci, Lactobacilli, and, Enterobacteriaceae were the major microorganism contaminants of the water at Vitacress. These bacteria were also the more persistent after water disinfection on the sanitizing tank. Results of population characterization showed that the water disinfection process is very efficient, allowing microbial load reductions in the worst case of 1 log and in the best case a total microbial load reduction, no matter the product tested (NaOCl or NEOW). NEOW showed similar efficiencies, in reducing the total mesophilic counts, as the traditional chlorine, with the advantage of the free chlorine concentration of NEOW (29 ppm) being lower than the concentration of chlorine of traditional NaOCl (60-90 ppm). Free chlorine generated by NEOW is a good alternative to NaClO and meets the objective of reducing free chlorine doses.
The obtained 1 to 2 log reduction in the decontamination of Vitacress ready-to-eat salads is typical of this industry and Vitacress intends to select NEOW as a disinfection method in the salad sanitizing tank.
Significance and benefits:
In the future, besides the clear reduction in chlorine dosage, a reduction in water consumption at Vitacress is also expected to be attained. In order to implement this technique, a continuous chlorine (from NEOW) dosing system will be adopted, since the same water can be efficiently used for 4 to 5 days. Also, cost savings in electricity for chilling the washing tank water and savings on water discharge will also be explored. In support of the adoption of this selected technology, the use of NEOW complies with the biocidal EU Regulations of 528/2012 (European Commission, 2012) due for introduction in the near future.
Successful applications:
NEOW could also be applied in other industries where water contamination occurs.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.1 – Specification of applicable methods (2014).
SUSCLEAN D3.2 – Impact of alternative techniques on hygiene (2014).
SUSCLEAN D4.2 – Proposition integrating the reduction of waste water and chlorine consumption and alternative (2014).
SUSCLEAN D4.3 - Final proposition integrating the reduction of wastewater and chlorine consumption, and alternative techniques
Key result n°9: LCA modelling for the decontamination and sanitation operations
Workpackage: WP5 - Environmental assessment and best practices integration
Research aims and background:
One of the main objectives of SUSCLEAN was to contribute to the development and implementation of a new generation of environment-friendly equipment sanitation and food product decontamination technologies. Despite the consumption of chlorine and water which were the two main environmental parameters to be evaluated, the environmental impact of technologies spreads out along every stage of their life cycle, from the extraction and transformation of the raw materials, to the use stage, until the final disposal of waste back to the environment. For this reason, a life cycle perspective is required when assessing the performance of technologies. Life Cycle Assessment (LCA) is a well-established methodology normally used to assess and compare the environmental impact of products, but it has also been used to assess environmental impact of technologies.
SUSCLEAN has used the Life Cycle Assessment (LCA) methodology to evaluate the environmental performance of the new techniques aimed to reduce the consumption of water and chlorine in the decontamination and sanitation operations at MPV processing plants.
The comparative life cycle assessment requires the definition of consistent material/energy flow models for both processes, including within the boundaries of the studied systems all upward, core and downward activities related to the MPV production, as the use and disposal of materials, energy and wastes. To enable a wholesome and consistent comparison between the benchmark process and the promising alternative techniques the system boundaries have to include all processes involved in the use of these technologies.
Results and applications:
Material/energy flow net models of the benchmark sanitation and decontamination have been created. The modular structure enables a precise allocation of ecological expenditures either to the different substances (e.g. potable water, sodium hypochlorite, etc.) or specific process steps (e.g. intermediate rinsing, wastewater treatment, etc.). Furthermore, the model structure enables an easy implementation of the alternative techniques by simply exchanging one single transition which is specific for the considered technique, e.g. the preparation of sodium hypochlorite for the benchmark in comparison to the generation of NEOW as one of the promising alternative techniques. This way a comparison within consistent system boundaries can be achieved since all other aspects are being kept constant.
Adequate boundaries of the systems have been defined for a consistent LCA comparison of each technique (See figure 3 in the attached pdf, the boundaries for sanitation system).
The inventory data for developing the LCA of the core processes come from the inventory data from Vitacress installation, the experimental work carried out in SUSCLEAN project, peer-reviewed literature and sectorial reports and the commercial data bases as GaBi and Ecoinvent v2.1.
The environmental assessment is performed according to the ISO standards on LCA (ISO 14040) and the main steps described in ISO 14044.
The LCA studies have been carried out using the two LCA tools used by the partners involved: umberto® (TUBS) and GaBi® (AINIA).
Significance and benefits:
The definition of consistent material/energy flow models for both equipment sanitation and decontamination of MPV processes has enabled the environmental assessment of the most promising techniques (NEOW, O3/UV, PEF) but also will enable in the future the assessment of new techniques.
Successful applications:
LCA methodology has been successfully used to evaluate the environmental performance of the new techniques aimed to reduce the consumption of water and chlorine in the decontamination and sanitation operations at MPV processing plants.
The modular structure of the material/energy flow models developed for the benchmark sanitation and decontamination processes could be used for further assessments of new alternative techniques.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
Alfredo Rodrigo, Mandy Wesche, Irene Llorca and Stephan Scholl. 2014. Environmental assessment of new decontamination and sanitation techniques for fresh-cut products-SUSCLEAN Project. Fouling & Cleaning in Food Processing. Green Cleaning University of Cambridge. 82-88.
Deliverable D5.1 Assessment of techniques and strategies as BAT
Deliverable D5.2 Inventory analysis of environmental benefits for emerging techniques and strategies.
André Paschetag. 2014. Ökobilanzielle Bewertung des Reinigungsverfahrens einer Produktionsanlage von "Fresh-Cut Food"-Produkten. Diploma thesis. Institute for Chemical and Thermal Process Engineering, TU Braunschweig.
Key result n°10: Environmental assessment of NEOW as alternative decontamination technique
Workpackage: WP5 - Environmental assessment and best practices integration
Research aims and background:
The amount of water and chemical detergents used for washing, cleaning and disinfection in the MPV industries as well as the toxicity of the chemical agents are key indicators of environmental performance in this sector. The most widely used disinfectants in MPV industries are chlorine-based compounds despite their potential environmental and health risks with respect to the possible formation of carcinogenic cleaning-by-products (CBP), e.g. trihalomethanes [Gil et al. 2009, Ölmez and Kretschmar 2009, Gray 2014]. For this reason, chlorine is on the list of toxic substances that the EU is aiming to reduce in the sector of the food, drink and milk industries (FDM) [Regulation (EC) 166/2006, E-PRTR]. Within the SUSCLEAN project new disinfection technologies and strategies are under development to reduce the consumption of water and chemicals and identify the most sustainable alternative technique. A life cycle assessment (LCA) approach together with a multi-criteria assessment have been chosen in the project to evaluate the environmental performance and generate environmental key parameters.
Results and applications:
In the initial multi-criteria assessment approach, a holistic evaluation of technical, economic and ecological aspects has been performed and the most promising techniques for decontamination, sanitation and water treatment have been identified. In the case of decontamination the neutral electrolyzed oxidizing water (NEOW) has been determined as the most promising alternative technique.
As basis for the evaluation of the ecological performance of alternative techniques, a decontamination and sanitation process from a typical production plant in the MPV industry have been defined as benchmark. Consistent system boundaries for all techniques have been defined for the LCA to enable a reliable comparison between the different alternative techniques and the established benchmark in regards to their environmental performance. Detailed dataset from the project partners responsible for the lab, pilot plant and industrial scale tests builds the basis for the LCA.
The LCA has been carried out with material flow net modelling tools. The created models enable an easy comparison of alternative techniques and the possibility to rapidly implement new data. Furthermore, sensitivity and focus analyses have been conducted to identify the ecologically most critical substances or process steps of the investigated technique and thus give recommendations for potentials of improvement to the other WP.
On lab scale NEOW demonstrates roughly the same ecological performance as the benchmark decontamination technique with NaOCl while offering an at least equal antimicrobial activity, less hazardous residues in the waste water and easier measurement and control possibilities. The most critical process parameters from an environmental perspective are the salt input and electrical energy consumption of the NEOW generator.
On industrial scale NEOW had a worse ecological performance than the benchmark processes due to the yet unoptimized state of the NEOW generator. The environmentally most critical parameters were still the salt input as well as the electrical energy consumption.
Significance and benefits:
The integration of ecological considerations in an early stage of the design process for new disinfection techniques and strategies in the MPV industry enables the identification of the ecologically most beneficial alternatives throughout the design phase. It was shown, that it is possible to utilize consumption data from different scales for an ecological assessment of a process with a suitable material flow net model.
Successful applications:
NEOW has shown good hygienic performance results at lab scale and it had low effects on salad quality. NEOW is expected to achieve a higher level of protection of the environment in comparison to chlorine based disinfection techniques but needs to be further optimized in regards to process parameters and has to be validated at industrial scale.
References
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
Gil, M. I., et al. 2009. Fresh-cut product sanitation and wash water disinfection: Problems and solutions. International journal of food microbiology. 134. (1): 37-45.
Gray, N.F. 2014. Chapter Thirty-One - Free and Combined Chlorine. Microbiology of Waterborne Diseases Microbiological Aspects and Risks (Second Edition). Academic Press: 571-590.
Ölmez, H. Kretzschmar, U. 2009. Potential alternative disinfection methods for organic fresh-cut industry for minimizing water consumption and environmental impact. LWT-Food Science and Technology. 42 (3). 686-693.
REGULATION (EC) No 166/2006 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 18 January 2006 concerning the establishment of a European Pollutant Release and Transfer Register and amending Council Directives 91/689/EEC and 96/61/EC
Key result n°11: Environmental assessment of the reuse of water at washing step after a O3/UV treatment
Workpackage: WP5 - Environmental assessment and best practices integration
Research aims and background:
The washing step is one of the main water consuming steps in the processing of fresh cut vegetables. In this step (see in the attached pdf figure 4: Pilot plant: washing step with a loop to treat a stream of washing water with O3/UV), salad is transported to a first washing tank or to a shower line where vegetables are washed with drinking water to remove debris, and then optionally directed to the disinfection tank. There is a continuous input of drinking water to maintain the quality of the washing water in a way to prevent the cross contamination along the processing period. The consumption at this stage can round between 3-6 m3 drinking water /h, or even more than 12 m3/h when the disinfection step with chlorine does not exist, as it happens in some EU countries.
Reuse of water at this step was identified as one of the best strategies to reduce significantly the water consumption in MPV plants. As described in another key result, the reuse of water at washing step after a O3/UV treatment allow to reduce water consumption in around 20%, while maintaining the hygienic level of the washing water.
However, the environmental impact of technologies spreads out along every stage of their life cycle, from the extraction and transformation of the raw materials and energy, to the use stage, until the final disposal of waste back to the environment. For this reason, a life cycle perspective is required when assessing the performance of technologies.
This report present the results of the LCA of the O3/UV technique in comparison to the standard technique based on the continuous use of fresh water.
Results and applications:
An attributional LCA environmental assessment was performed according to the ISO standards. LCI is based on on the results of the pilot plant scale tests performed in AINIA within the WP4 of the SUSCLEAN project, literature sources and commercial databases (PE International 2006), and Ecoinvent v2.1 database). CML 2001 method has been used for the environmental assessment. The functional unit for decontamination process is to “achieve the required level of decontamination in 1 kg of clean lettuce or 1 kg of baby leaves”.
The reuse of water at washing step allowed to reduce the direct water use in the all decontamination process by 16% compared with the reference scenario (without water recirculation). Reuse of water after O3/UV treatment also reduces the water consumption from a life cycle point of view since less indirect water consumption (associated to the electricity production) was required for water conditioning and water cooling.
The electricity consumption is slightly lower in the case of water recirculation because the electricity needed for the O3/UV treatment is compensated by a lower electricity consumption required for water cooling and water conditioning. Also the consumption for wastewater treatment is lower due to a partial oxidation of the COD in the O3/UV treatment.
Finally, the results of the comparative LCIA for the reference decontamination technique and O3/UV technique were very similar values in all impact categories (see table 1 in the attached pdf), with slightly lower impacts for the water recirculation scenario.
Significance and benefits:
On a life cycle perspective, the reuse of water at washing step after an O3/UV treatment allowed a significant reduction on water consumption, a slightly lower energy consumption, no chemical consumption, no reaction by-products and lower organic load in wastewater. Furthermore, environmental performance based on the environmental indicators (CML 2001) was slightly better for the O3/UV technique compared with the conventional technique.
However, the reuse of water at washing step after an O3/UV treatment should be tested at industrial scale to confirm the results obtained.
Successful applications:
The reuse of water at washing step after an O3/UV treatment could be also investigated to be applied on the washing step of other vegetables and fruits. A complete LCA is required for assessing the overall environmental performance of the technique from a life cycle perspective.
References:
Alfredo Rodrigo, Mandy Wesche, Irene Llorca and Stephan Scholl. 2014. Environmental assessment of new decontamination and sanitation techniques for fresh-cut products-SUSCLEAN Project. Fouling & Cleaning in Food Processing. Green Cleaning University of Cambridge. 82-88.
Deliverable D4.3 Final proposition integrating the reduction of waste water and chlorine consumption, and alternative techniques.
Deliverable D6.6 Recommendations to the IPPC Guidelines for cleaning-suited equipment.
Deliverable D5.2. Inventory analysis of environmental benefits for emerging techniques and strategies.
Potential Impact:
Potential impacts
The European added value of the project lies in increasing the innovation capacity of the equipment manufacturing industry. SUSCLEAN has proposed hygienically enhanced MPV processing equipment integrating innovative sanitation techniques, together with optimised and alternative decontamination techniques, for use along the supply chain.
The innovations will target food safety and quality improvements and could be listed as follows:
o Alternative chemical and physical procedures for product washing operations reducing both wastewater and chlorine,
o Alternative chemical sanitation techniques reducing the use of chlorine,
o Equipment design principles to facilitate cleaning and disinfection and to be able to induce new environmentally friendly sanitising procedures,
o Rapid microbiological diagnostic techniques potentially allowing positive release of MPV products and helping decision makers to change to alternative decontamination strategies.
The work on characterising biofilm development and cross-contamination to food products, together with biofilm sanitising strategies will be of interest to other food industry sectors and other industries concerned in which biofilms pose a hygiene hazard (biotechnology, pharmacy, cosmetics).
The European added value lies in strengthening the competitiveness of the European fresh-cut food industry. Improvements in production sustainability, food safety and BAT were developed with the industrial partners involved in the consortium.
SMEs involved in the project as two equipment manufacturers (washing systems, cleaning/sanitising tools), two microbial contamination kit development companies (rapid surface contamination tools) will develop or has already developed their field of expertise, providing the MPV industry with competitive technical advantages over their major US and South American competitors.
The assessment of the cost-effectiveness and technical practicability of the new decontamination and sanitation techniques leaded the end-user project partner to integrate these innovations. Other companies of the MPV sector and in particular SMEs were informed on the potential benefits from these advances through dissemination activities (e.g. workshops, practical guides). Two other end-users (large European industries) were involved in the project as advisers increasing the impact of the novelties brought by the project.
The collaboration between academic research partners and SME research and development stakeholders in SUSCLEAN has supported some development of innovative techniques in SMEs that should increase their competitiveness as compared with multinational groups. Good examples are the two diagnostic tools companies and the equipment manufacturer.
The company image using validated environmentally friendly techniques in MPV production will be enhanced in the customer’s point of view and therefore economically beneficial for SMEs.
The European added value lies in offering improved food products of high quality and safety. SUSCLEAN was able to provide stakeholders with rapid diagnostic tools against microbial contamination allowing end-users to envisage real-time corrective actions. A predictive models taking into account the impacts of decontamination treatments and microbial dynamics to estimate the reduction in public health disease burden. Product washing and equipment sanitation conditions proposed were studied against any potential induction of any emergence of virulence and resistance of microorganisms. Guidance to improve food quality was delivered highlighting the benefits from innovative techniques.
The research has contributed to sustainability in general and, more particularly, to the EC Directive on Integrated Pollution Prevention and Control (IPPC), in terms of reducing chlorine emissions in water and decreasing water consumption rates in food industries by up to 20-50 % via a revision of the relevant best available techniques reference document(s). Upgraded BAT were proposed to the European Commission targeted to reduce chlorine, waste water and consumption thanks to alternative decontamination and sanitation solutions.
The project has resulted in numerous theoretical, technological and societal outcomes of which exploitation may lead to important fundamental and applied spin-offs. The impacts defined at the start of the project (scientific, technological and societal) were updated and are now presented (see in the attached pdf table 2: Project scientific results, table 3: Project technological results and table 4: Project societal results).
Main dissemination activities and exploitation of the results
The project website was regularly updated with dissemination materials dedicated to the general public as general project brochure into national languages, some research summary sheets to inform the industry and SMEs in their mother tongue. A webinar was available in August 2014 to inform the general public of the progresses of the project. According to the website statistics, there were 693 visitors in year 2013, 2024 visitors in the year 2014, generated total 2853 pageviews in year 2013, and 9006 pageviews in year 2014, respectively.
In parallel to a continuous dialogue with the industry, personal consultations of SMEs or through dedicated workshops were carried out. Workshops were organized in Spain, Portugal, Hungary, The Netherlands (for both Germany and The Netherlands), United Kingdom and France. The goal was the presentation of the available results and collecting stakeholder’s feedback on research needs and the applicability of the project results.
The workshop in Wageningen (Nl) merged with the last general assembly of the project was devoted to the following question: Less water and no chlorine in the fresh-cut food industries: a dream?
A discussion was initiated between the project participants of three FP7 project, Susclean, Veg-i-trade and Resfood and the industry (SMEs and Large industries) from the Netherlands and from Europe at large and with the Ministry of Health in the Netherlands. The Ministry of health agreed for the Netherlands on the necessity to update the law, followed by most of the industrials and based on the projects’ breakthrough. The main constraints to go further are public health, sustainability of the fresh-cut food industries and the European market depending on the local legislations.
The network of the National Technology Platforms of the European Technology Platform “Food For Life” was contacted and their members were asked to distribute the new knowledge. For increasing the publicity of the SUSCLEAN results and taking benefit from the synergy with the practical results of other FP6-FP7 projects in the food, diet and health area, a workshop was organized under the NTPs of ETP “Food For Life” on presenting 13 projects beside SUSCLEAN having practical results for the industry on 2nd December 2014 in Brussels.
The project results were presented at international scientific conferences as “Green Cleaning” in Cambridge (Fouling and Cleaning International Congress), EFFOST (Invited speaker in Uppsala), the 12th International Chemical and Biological Engineering Conference (Chempor in 2014), or at national events as the bi-annual ENVIFOOD meeting point conference at Madrid (Spain), at a seminar with an exhibition in the Netherlands during the Dutch Food Valley EXPO about hygienic design for the fresh cut industry, at open days for companies as Campden BRI, under BacFoodNet (COST Action FA1202), at a workshop organized at Murcia by the CSIC (Spain), at Process Net Annual Conference 2014 (Aachen, Germany, 2014), at the 2nd Annual FDG Meeting, (Braunschweig, Germany, 2014) and at Umberto User-Workshop (Hamburg, Germany, 2014).
Towards the general public in addition to information available on the website, a guide on “Safe handling of fresh fruits and vegetable at home” for consumers was prepared in August 2014 and was communicated through the CommNet network.
Three documents entitled “Code of the Best practices for Cleaning and Disinfection” and “Guideline for Cleaning Suited Equipment” and “Recommendation to the IPPC” were written. The guidelines include protocols and procedures to integrate the techniques developed and improved by SUSCLEAN in the MPV supply chain.
List of Websites:
Project public website
Relevant contact details:
SUSCLEAN Coordinator:
Thierry Benezech
Directeur de recherche INRA
UMET
Equipe PIHM
Tel : +33 3 20 43 54 12
Fax: + 33 3 20 43 54 26
E-mail : Thierry.Benezech@lille.inra.fr
SUSCLEAN Project Manager:
Léa Tourneur
INRA Transfert (IT)
3 rue de Pondichéry
75015 Paris, France
Tel : +33 (0) 1 76 21 62 06
E-mail: lea.tourneur@paris.inra.fr
SUSCLEAN has as its strategic goal to contribute to the development and implementation of food product decontamination technologies and equipment sanitation conditions which are environment-friendly while ensuring food safety. The two key targets are the reduction or replacement of chlorine and the mitigation of the process water. For this purpose, the project has developed knowledge, methods and tools for the following activities:
- Characterization and the monitoring of the microbial contamination patterns
The sampling campaigns in large MPV industries showed that chlorine has a real effect on the level of product contamination and brings a significant protection against cross contamination from washing water. The colonization patterns of pathogenic E. coli O157 strains showed allelic variations in the general-stress response and survived significantly shorter on lettuce compared to strains showing wild-type sequences. The fresh-produce environment selects for stress-resistant strains that are subsequently a higher risk for public health. Viral pathogens (HAV) inactivation showed that the classical chlorine treatment and alternative chemical treatments as peracid formulation were not able to reduce by 4 log. Extension of predictive microbiology models/software and development of general risk assessment tool was proposed.
- Improving the hygienic design of equipment (geometry and surface)
E. coli did not grow into biofilms as on standard steel surfaces with hard diamond-like carbon coatings modified with oxygen (SICON) and the antimicrobial coating modified with Ag. Beneficial geometrical changes in terms of hygiene can be proposed for the washing tanks based on modelling using specific Computational Fluid Dynamics tools. New design options in pertinence with the European Hygienic Engineering and Design group induced longer periods before any significant growth of the biofilms in washing tanks at least over 24 h. A comprehensive document was written to list and detail the hygienic design requirements for the different part of the processing lines.
- Designing new decontamination approaches for fresh-cut food and sanitation strategies
The most promising methods were chosen amongst the following list on surface, water and products: phytochemicals, chlorine dioxide, ozone, hydrogen peroxide, organic acids, enzymes, copper suspension, pulsed UV light, pulsed electric fields, NEOW and ultrasound. NEOW was selected and tested at pilot plant scale with the advantage of on-site production, being less corrosive and effective at lower chlorine concentration. The organoleptic properties of the product, as well as the treatment impact on the salad shelf-life were not affected by the treatment. Potential benefits of using ultrasound technique to reduce the need for high chlorine concentration were identified at laboratory and pilot plant scale. Another promising approach is to use PEF (Pulsed Electric Field) together with a lower concentration of chlorine, which was tested at pilot-plant scale. Ozone and UV were selected together to treat water and it was possible to reach a water reduction up to 42% with lower water/lettuce ratio, keeping the same hygienic level of washing water. Additionally, a reduction in water consumption will be attained if a continuous dosing system is adopted whereby the same water can be efficiently used for 4 to 5 days.
- Proposing guidance and recommendations to renew the best available processing techniques (BAT); assessing the impact of sanitation and decontamination strategies in line with the Directive on Integrated Pollution Prevention Control (IPPC) 2008/1/CE;
Inventory analysis on water, chloride and energy consumption as well as wastewater production in disinfection and sanitation processes at a reference plant was carried out in collaboration with a company. Life cycle assessment was carried out for the above selected techniques for industrial or pilot plant scale testing. A sensitivity analysis was carried out to identify key parameters for the LCA in sanitation and decontamination processes.
Project Context and Objectives:
The market of ready-to-use minimally-processed vegetables (MPV) has grown rapidly over the recent decades. Chlorine has been widely used to decontaminate fruits and vegetables in the fresh-cut industry in order to reduce the load of microbial contamination. The association of chlorine with the possible formation of carcinogenic chlorinated compounds and the excessive water use prompted the European Commission to finance research into the development of alternative sustainable cleaning and disinfection methods.
The other challenge for the MPV industry is the minimization of water consumption and wastewater discharge rates which is considered as huge nowadays. More than 30 l per kg of products could be used in countries where the use of chemicals in the process is forbidden.
Hence some EU countries as in the Netherlands, Belgian and UK forbid its use for safety reasons. There is no common regulation throughout Europe on the use of chlorine for fresh-cut food processing. There are now discussions at the political level in countries like the Netherlands and Belgian on the possibility to accept the use of disinfectants as Chlorine in the fresh-cut food industries.
Food cross contamination could not be avoided during product washing operations with a view of water consumption reduction in conjunction with food production sustainability. The other issue is that some legislation in Europe demands an acceptable contamination threshold of the final product. In France the legislation impose less than 106 CFU per g of product which is impossible to achieve with no help of any chemicals in the washing systems.
SUSCLEAN advances are thus aimed at mitigating water and reduce or replace chlorine consumption whilst taking into account environmental and food quality impacts for the fresh-cut food industry to answer to the double challenge of less water and if possible no chlorine.
SUSCLEAN has as its strategic goal to contribute to the development and implementation of a new generation of equipment sanitation and food product decontamination technologies which are environment-friendly while ensuring food safety. Sanitation includes cleaning which is the action of removing all organic matter up to biofilms and disinfection which consists of decreasing the viable microbial population on food processing surfaces, with special attention paid to pathogens.
For this purpose, the project developed knowledge, methods and tools aimed to:
- characterize and monitor the microbial contamination patterns,
- improve the hygienic design of equipment for the fresh-cut product industry
- design new decontamination approaches for fresh-cut foods and sanitation strategies (cleaning and disinfection procedures) for their processing equipment along the supply chain;
- propose guidance and recommendations to renew the best available processing techniques (BAT); assess the impact of sanitation and decontamination strategies in line with the Directive on Integrated Pollution Prevention Control (IPPC) 2008/1/CE.
These scientific and technical advances will help to reduce the use of water and chemicals (noticeably chlorine), while ensuring food safety, sustainable practices and preserving food quality in the European fresh-cut food industry.
The project objectives could be detailed as follows:
At the scientific level,
- Determine the points of microbial food product contamination at the critical food processing stages;
- Understand colonization patterns of spoilage and pathogenic microorganisms at these points, both on food and processing equipment;
- Develop model colonization systems that can be used for sanitation and decontamination studies;
- Investigate sensitivity of microorganisms (essentially bacteria) to cleaning and disinfection procedures and identify any mechanisms developed by these microorganisms to resist disinfection procedures;
- Characterize the impact of new sanitizing and decontamination alternatives on pathogen virulence and infectivity;
- Characterize the role played by equipment geometry and materials – at the macro, micro, and nanometric scales – in microbial contamination patterns and persistence;
- Assess the environmental impact of existing and improved sanitation and decontamination treatments along the MPV supply chain;
- Develop of predictive models to consider the impact of microbial colonization of food processing surfaces on MPV colonization, in conjunction with applied sanitation and decontamination treatments;
- Develop microbiological testing protocols with the potential of detecting specific pathogenic microorganisms that may, by detecting any contamination within one hour, allow a quick positive release of MPV products.
At the technological level,
- Conceive, benchmark, and propose alternative sanitation treatments suited for equipment cleaning and disinfecting procedures along the MPV supply chain;
- Conceive, benchmark, and propose alternative chemical and physical MPV decontamination treatments;
- Optimize the use of chlorine in MPV decontamination;
- Design and test sanitation and decontamination operations aimed at tailoring the use of water;
- Establish guidelines to hygienically design equipment to ease the cleaning procedures;
- Evaluate impacts of alternative decontamination strategies on nutritional and sensory properties of MPV;
At the societal level,
- Renew the code of best MPV processing practices with respect to sanitation and decontamination;
- Issue recommendations to the EC;
- Transfer the gained knowledge to the European industry, in general, and to SMEs in particular.
Project Results:
Key result n°1: Microbial contamination and persistence
Workpackage: WP1 - Microbial contamination and persistence along the food chain
Research aims and background:
The market of ready-to-use minimally-processed vegetables (MPV), has grown rapidly over the recent decades. Chlorine has been widely used to decontaminate fruits and vegetables in the fresh-cut industry in order to reduce the load of microbial contamination. However, the association of chlorine with the possible formation of carcinogenic chlorinated compounds and the excessive water use prompted the European Commission to finance research into the development of alternative sustainable cleaning and disinfection methods. The development these alternative methods require a deeper understanding of the biodiversity and colonization pattern of pathogenic and non-pathogenic (i.e. spoilage) microorganisms. In addition, the efficiency of newly developed decontamination method should be evaluated for truly pathogenic microorganisms. Insights on the contaminations scheme of industrial sites and further understanding of microbial colonization patterns will be helpful in redefining quality systems and intervention strategies.
Results and applications:
Contamination levels of equipment surfaces was found to be high but variable (0.7 to 10.5 log10 CFU/sample). Washing in product in water with chlorine reduced the microbial load significantly compared with washing in only water but at the end of shelf-life (which was longer for the product washed in chlorinated water) was the same. Many of the bacterial isolates obtained from the processing facility were able to grow and form biofilms in the laboratory at temperatures as low as 10 degrees Celcius and some of these were found to be highly resistance to chlorine. Laboratory experiments were conducted to study the survival of highly pathogenic E. coli (EHEC) on cut lettuce. It was observed that survival was strain dependent, ranging from no decline to 2 log decline over 3 weeks. We identified a suitable genetic marker for survival: the general stress response gene rpoS. Strains with a wild-type rpoS gene were significantly better survivors. In addition, these strains were higher resistance to an acid shock mimicking the human gastric barrier. This indicates that the presence of EHEC in this environment selects for stress resistant strains which form an increased public health risk. Washing product contaminated with EHEC in chlorinated water and electrolyzed water as an alternative model reduced the pathogen by on average 2.5 log, which is one log more as with only water. However, large strain variation was observed. With respect to the inactivation of Hepatitis A virus, the classical chlorine treatment as well as alternative peracid formulations were not able to reduce the recommended 4 log reduction (maximum reduction was 1.5 log). Biofilm growth of non-pathogenic (spoilage) bacteria can be prevented by 30 ppm of chlorine when the biocide is present from the first stage of the biofilm initiation. However, once settled and spatially organized, and as observed in different industries, biofilms are very difficult to eradicate. Finally, a risk assessment tool was developed by which the industry can assess and optimize the use of disinfectants in their processes regarding the inactivation of microbes given a number of parameters (i.e. concentrations, pH, temperature).
Significance and benefits:
Our results showed that microbial contamination in the vegetable industry can be high, but most of this are spoilage organisms. The addition of a disinfectants to the washing water will prevent cross-contamination and will prevent biofilm growth on equipment. However, already established biofilms are extremely difficult to remove. In addition, biofilms formed by non-pathogenic bacteria can trap pathogens which are subsequently protected by sanitation actions. Finally, food safety interventions taking by the industry should not be focused on the actual removal of pathogens from the product since the efficiency is limited and highly variable. In the end, the prevention of contamination during primary production in the field remains the most important factor with respect to fresh produce safety.
Successful applications:
As a spin-off of the SUSCLEAN a project was started financed by the fresh-cut produce industry to construct a risk assessment model that assesses the public health relevance of cross-contamination in the washing step of fresh-cut produce processing. In some EU member states, like The Netherlands, the use of disinfectants in the water is prohibited. However, the industry in these countries apply force to the government to allow the use of disinfectants in the washing water. The main argument is to prevent cross-contamination by pathogens and thereby provide an intervention to possible outbreaks. However, we showed that the public health relevance of cross-contamination very limited and only relevant in extreme (i.e. unlikely) contamination events. Together with the experimental results of SUSCLEAN showing a limited efficiency with respect to pathogen removal this questions the necessity of using disinfectants in the washing water. However, in the situation like in The Netherlands, the quality of the water relies on continuous addition and refreshments of washing baths with large amounts of potable water to minimize the event of accumulation of micro-organisms in the water and transfer of micro-organisms from the water to the product. This prompts the necessity to study the balance between food safety and sustainability in terms of water and energy use. This should be focus of future projects in this area.
References
A very successful workshop entitled “less water and no chlorine: is it a dream?” was held in Wageningen (The Netherlands) on December 4th. The results of three European projects dealing with a similar topic were presented (Vegitrade, Resfood and Susclean), followed by an afternoon of mediated discussion with people from industry, science and policy.
Several scientific papers are in preparation on:
1. Microbial contamination along the production line of a large-scale fresh-produce processing facility.
2. High-throughput real time assessment of biofilm formation of isolates obtained from machinery and products of large-scale scale fresh-produce processing facility.
3. Survival of pathogenic E. coli and Hepatitis A on lettuce and resistance to disinfectants.
Key result n°2: Hygienic design evaluation: new surface alteration to prevent food product cross contamination and reduce environmental impact of processing and cleaning operations in the fresh-cut food industry
Workpackage: WP2 - Design of equipment to mitigate microbial contamination and persistence
Research aims and background:
In pursuit of the reduction of the consumption of water and chlorine in minimal processing fruit and vegetables (MPV) productions, food companies are potentially facing increasing microbial risks due to bio-film formation on food production surfaces, transfer of contamination to the product and/or inadequate decontamination of MPV products.
Hence surface properties are known to impact adhesion of bacteria and the subsequent growth of biofilms.
Different strategies to mitigate product contamination during the washing of produce could be proposed as:
- increasing bacterial adhesion on tank surfaces to lower the bacterial concentration in the washing liquor,
- avoiding bacterial adhesion to reduce the potential formation of biofilms,
- lowering the attachment strength of the bio contamination to enhance the ease of cleaning.
The washing tanks are not exclusively concerned and this could be expanded towards the other equipment in the fresh-cut processing lines as chopping machines, conveyor belts, packaging machines, etc.
Results and applications:
Key parameters of the micro and nano surface topography and of the surface energy were identified based on their consequences on microbial adhesion and biofilm development.
Different types of stainless steel surface coatings were studied such as hard diamond-like carbon (DLC, a-C:H) coatings modified with silicon and oxygen (a-C:H:Si and a-C:H:Si:O called SICAN and SICON), Fluorine DLC and antimicrobial coatings prepared by sputter techniques as Silver (Ag), Ag modified a-C:H (a-C:H:Ag) and titanium dioxide TiO2 known to have photocatalytic properties.
Analytic investigation concerning the deterioration behaviour of the coatings were considered. Here methods like Infrared (IR) spectroscopy, SIMS (Secondary Ion Mass Spectrometry) and contact angle measurements were applied. Especially for the modified DLC coatings an increase of the surface energies was revealed after exposure with acids and hydroxides. The main reason for this behaviour was a clear increase of the polar component of the surface free energy.
Surface energies were found to be affected by the presence of organic/chemical compounds found in the detergent, water and the washing liquor. Such surface conditioning was found to reduce differences in the surface energy of the different coatings proposed. However a quite large range of surface energies was tested from 31 mJ/m² (Fluorine DLC) to 50 mJ/m² (2B finished AISI 316 stainless steel electropolished) combined with three average surface roughness from 1 m (microbeaded statinless steel), 0.3 (Standard 2B AISI stainless steel) and 0.1 m for the other options tested.
No beneficial effects were found in washing tanks in terms of reduction of the microbial trapping and on the subsequent biofilm growth with Pseudomonas species. Laboratory experiments with Escherichia coli showed similar results as no impact on the bacterial adhesion was detected but SICON and the silver-DLC coatings were found to reduce the biofilm growth for different reasons.
Product hold-up effect was studied with some of these surfaces. The objective was to evidence any beneficial effect of the surface properties on the attachment of i.e. salad leaves to the surfaces. Some interesting effects were found regarding the reduction of product holdup as too smooth surfaces or hydrophobic ones induce significantly product attachment. Wet produce as demonstrated with salad leaves deeply enhance the attachment on surfaces.
Significance and benefits:
Even if this study highlights the need of additional work to be able to define precisely the areas of applicability of surface coatings, the strategy of surface properties alteration remain definitely a key to the future. Commonly used sanitizing methods were shown to negatively affect the performance of the new surfaces which is a major drawback in their application to current industrial processes.
Any improvement in the reduction of the environmental impact of food processing would emerge from an integrated approach including surface alteration, equipment geometries and processing and sanitizing conditions.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.2 – Hygienic design recommendation and significance (2014)
Key result n°3: Hygienic design principles a way to prevent food product cross contamination and reduce environmental impact of processing and cleaning operations in the fresh-cut food industry
Workpackage: WP2 - Design of equipment to mitigate microbial contamination and persistence
Research aims and background:
The fresh-cut, minimally processed fruit and vegetable (MPV) market is of increasing importance to the food sector with dramatic growth having been observed in recent years, FAO (2010). This growth is thought to have been stimulated by the increased knowledge of consumers about the role of fruit and vegetables in a healthy diet coupled with a consumer need for convenience.
Food safety is not negotiable and within the global strategy to avoid any outbreak related to fresh cut food, hygienically designed machineries involved in the processing and packaging of such products appeared to be mandatory.
The related objective is that any change in the product washing and equipment cleaning operations towards a significant mitigation of the environmental impact due to the consumption of water and chemicals is jeopardized by machineries not hygienically designed. This is unfortunately the case for the equipment widely used in this food sector.
Background information on hygienic design can be found in sources including:
• Machinery Directive 2006/42/EC (formerly 98/37/EC)
• EN 1672-2:1997: 2005+A1: 2009 Food processing machinery-Safety and hygiene requirements-Basic concepts-Part 2; Hygiene requirements.
• ISO 14159:2002 Safety of machinery -- Hygiene requirements for the design of machinery.
• Publications of the European Hygienic Engineering Design Group www.ehedg.org.
• Publications of the 3-A association in the USA www.3-a.org.
• Publications of the National Sanitation Foundation in the USA www.nsf.org.
• Regulation (EC) 2023/2006 on good manufacturing practice for materials and articles intended to come into contact with food.
Results and applications:
A comprehensive guideline document was produced to document hygienic design best practice in the minimally processed fresh cut fruit and vegetables sector including cantaloupe processing.
It addresses the need to understand critical hygienic design factors in 4 main areas:
1. The speed of produce transit through washing systems
2. Equipment design to minimise product hold up and thus minimise washing times
3. Equipment design features that make it difficult to clean and would extend cleaning time/chemical use
4. Poor hygienic design features which are un-cleanable and could harbour microorganisms.
Equipment manufacturers are required according to the Machinery Directive to state the intended use of the equipment. When designing the equipment, manufacturers should also identify all the hazards associated with its intended use and undertake a risk assessment to design the equipment to eliminate hazards where possible. If the hazard cannot be eliminated through design then effective cleaning and disinfection instructions should be provided otherwise, additional information is required.
This information could include, for example: further monitoring, cleaning and disassembly instructions; specific processing conditions such as temperature controlled environments; limitations on the types of products that can be safely processed; and the requirements for any safety features to protect the operative.
Guidelines proposed by the Susclean project are strongly recommended as the available background information does not include the specific requirements for the fresh-cut food sector (vegetables and fruits). Data from the research activities of WP2 are available to strengthen the recommendations listed in these guidelines. The document focus is however broader than the washing tanks and address all the equipment and machineries involved in the fresh-cut food processing lines.
Significance and benefits:
These guidelines appeared as a new reference for this industry sector and should be a base for fresh product manufacturers to discuss and negotiate with equipment manufacturers.
Such guidelines document will be available for the industry and additional works are needed to have this document accepted by the EHEDG through the setting up of a working group of stakeholders to have these guidelines accepted and written under the EHEDG format. Anyway the partners involved in this work are members of the EHEDG and could be eligible to participate to the mentioned working group.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN 2.4 – Hygienic design principles (2014)
Key result n°4: Hygienic design evaluation of washing tanks: setting up a strategy to prevent food product cross contamination and reduce environmental impact of processing and cleaning operations in the fresh-cut food industry
Workpackage: WP2 - Design of equipment to mitigate microbial contamination and persistence
Research aims and background:
The reduction of the consumption of water and chlorine in fresh-cut food processing, industrials are potentially facing a microbial risk due to biofilm formation on technical surfaces impairing hygiene monitoring on the production site. Hygienic design principles are frequently not implemented in in-use equipment and machineries in the fresh-cut food industries.
A characterization at different scales of the influence of the design on biofilm development and resistance against cleaning operations was carried out. The foreground related to the mechanisms involved in biofilm installation and resistance was generated through studying the respective roles of the flow conditions, the presence or not of chemicals and kinetics of bacterial adhesion, biofilm development and biofilm removal.
Results and applications:
The criticality of the design was found to depend on three factors, the significance of the surface contamination, the biofilm growth kinetics’ shapes and the subsequent resistance to cleaning.
A strong beneficial effect of the proposed equipment geometry changes was observed:
- in the reduction of the microbial contamination trapping over the first few hours,
- with more than 8 hours delay in the biofilm development,
- in the biofilm structures observed and related to the hydrodynamics,
- In the subsequent resistance to cleaning.
The reduction of the microbial trapping is largely induced by the geometry modifications as open angles (over 100°) modifying the flow pattern with an increase in the wall shear stress (flow mechanical action). Moreover the biofilm growth kinetics were modified showing a lag phase which could cover more than 24 hours. Considering the processing time before any sanitation actions (8 hours as a whole day production), no significant bacterial growth could be seen allowing milder sanitation conditions (less chemicals and less water).
Splash areas were shown to be covered by three dimensional and dense biofilm structures. Hence, biofilms on surfaces strongly affected by the flow turbulences or located in protected areas against the flow shown very different structures. In protected areas, biofilms can grow in three dimensions with visible exopolymeric excreted substances and appeared to be significantly less dense that the ones impacted by the fluid motion (turbulences or splash zones) developing flat two dimensional structures.
The resistance to cleaning was found to be dependent on the biofouling structures. The most fragile biofilms against foam cleaning were those formed on vertical surfaces included the splash areas probably emphasized by any sliding of the foam during the cleaning process. The most resistant biofilms against foam cleaning were those formed on horizontal surfaces and/or grown in static conditions. Conversely the later appeared to be easily removed if cleaning includes chemicals and a mechanical action not always possible according to the machinery designs.
Enzymes were found to affect bacteria cells removal from surfaces by acting on the expolymeric substances present in the biofilms. No effect on the bacteria viability could be stated. A beneficial effect comparing to standard foam cleaning with chemicals was observed with biofilms grown in static conditions probably due the specific action of enzymes on the exopolymeric substances in the biofilm structure.
Depending on the areas concerned mechanical action (sanitation fluid flow) or not (foam cleaning and mild rinsing) could be carried out to get rid of the surface contamination. Anyway, aiming at reducing the criticality of washing tanks is also a question of compromises.
Flow modelling using specific Computational Fluid Dynamics tools was found to be useful to propose beneficial geometrical changes e.g. to avoid/reduce areas that are not or poorly accessible for the detergent i.e. forbidding any mechanical action, which are prone to be dead areas during the washing process.
Significance and benefits:
It can be thus stated that the risk of food cross contamination from the equipment surfaces is significantly reduced with the new geometries. Sanitizing strategies could be re-evaluated towards a higher efficiency while mitigating the environmental impact of such operations.
It is important to notice that the geometry improvements proposed in this work are in coherence with the European Hygienic Engineering and Design Group (www.ehedg.org) recommendations. This foundation is producing guidelines largely implemented in international and European standards and in the European legislation. The novelty here is the quantification of the consequences of the design improvement in terms of hygiene. Data obtained here are relevant to be used in risk analysis processes.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.2 – Hygienic design recommendation and significance (2014)
Key result n°5: Treatment of stainless steel equipment - Removal of biofilms with ultrasound
Workpackage: WP3 - Alternative equipment sanitising and MPV decontamination strategies
Research aims and background:
Ultrasound waves in liquids (e.g. in water) causes pressure variations which leads to cavitation. The implosion of the cavitation bubbles and the arising micro jets lead to a high local shear stress, which can remove cells from surfaces or even disrupt cell walls or membranes. Ultrasound waves in a frequency range of 20-100 kHz was used in several studies successfully for the deactivation of bacteria and cleaning of membrane fouling. For the decontamination of produce the use of ultrasound is limited, because of the heat development when sonication is used continuously. Nevertheless cleaning of stainless steel equipment with ultrasounds seems to be a promising alternative treatment for biofilm removal.
Results and applications:
To find the best working parameters a coupon with a biofilm layer in a saline solution was sonicated with different power settings for different durations with a 20 kHz sonotrode. At 50 % sonication power the killing and removal of the bacteria was inefficient, even after 5 minutes of sonication. At 100 % sonication power and a duration of 3 minutes the biofilm was completely removed from the stainless steel coupon. These results pointed out that the complete removal of biofilms with a 20 kHz sonotrode is possible. Another observation was that the sonication of the coupon additionally lowers the amount of microbial contaminations about 80 % in the surrounding liquid. An additional chemical agent could prevent cross contamination of the last 20 % of residual bacteria. All in all the treatment of equipment with ultrasound exhibit good results in laboratory scale experiments.
Significance and benefits:
An important advantage of ultrasound is that mechanical removal of biofilms is better than killing of the microorganisms with chemicals. Dead biomass is a possible starting point and anchor for new attachment and growth of microorganisms, because the dead cell mass is a nutrient donor for new populations to grow. Only mechanical removal can delay the biofilm formation.
Successful applications:
Cleaning of stainless steel surfaces in laboratory scale works successfully, but it is not possible to clean a complete industrial plant. Therefore the next step is to identify the critical zones, like dead zones etc., for the design a customised sonotrode.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.1 – Specification of applicable methods (2013).
SUSCLEAN D3.2 – Impact of alternative techniques on hygiene (2014).
Key result n°6: NEOW – an alternative to conventional sodium hypochlorite to prevent cross contamination in MPV industries
Workpackage: WP3 - Alternative equipment sanitising and MPV decontamination strategies
Research aims and background:
Electrolyzed Oxidizing Water (EOW) is obtained by an electro dialysis of a diluted salt solution. At the anode side an acid solution consisting of oxygen and chlorine gas, hypochlorite ions, hypochlorous and hydrochloric acid, and at the cathode side a basic solution consisting of hydrogen gas and sodium hydroxide accrues. To obtain the Neutral Electrolyzed Oxidizing Water (NEOW) the formed acid and basic solutions are mixed. This leads to a solution with is expected to be less corrosive and irritating. The big advantage of NEOW compared to sodium hypochlorite (NaOCl), which is typically used for the decontamination of minimally processed vegetables (MPV), is the on-site production. The effective component in both solutions is the hypochlorite ion, which penetrates the cell wall of bacteria and disrupts the membrane transport proteins resulted in a disrupted energy production. Because of further compounds in the NEOW like hydrochloric acid and sodium hydroxide a lower concentration of NEOW has the same decontaminating effect as conventional applied sodium hypochlorite.
Results and applications:
Washing of MPV (salad) with NEOW was compared to NaOCl and water. An unexpected result was that even the cleaning with NaOCl is not more effective than purging with water. This leads to the assumption that NaOCl is not decontaminating the salad in particular, but prevents cross contamination in the food processing industries. This discovery foregrounded the disinfection of the washing water, for which NaOCl is typically used at a content of free chlorine from 60 ppm to 90 ppm in MPV processing. The experiments of WP 3 and WP 4 (details see in D3.2 and D 4.2) pointed out that a similar reduction of contaminations in water can be achieved with NEOW at lower levels of free chlorine (29 ppm).
Significance and benefits:
The biggest benefit is the on-site production of NEOW with a generator and a diluted saline solution. For the experiments at laboratory scale a suitcase NEOW generator was constructed. At industrial stage a pilot plant was installed at Vitacress (see also key result of WP4: Optimizing cleaning and disinfection processes to reduce the use of water and chlorine, or D 4.3). The use of NEOW at lower levels of free chlorine is another big benefit.
Successful applications:
The NEOW technology was applied in a salad producing industrial side for large scale experiments. The results were very promising with respect to decontamination and product quality.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.1 – Specification of applicable methods (2013).
SUSCLEAN D3.2 – Impact of alternative techniques on hygiene (2014).
Key result n°7: Reduction of the water consumption: washing water reuse after O3/UV treatment
Workpackage: WP4 – Optimising cleaning and disinfection processes to reduce the use of water and chlorine
Research aims and background:
The MPV washing step was identified as a key process step where water consumption can be reduced, by minimizing water addition to the washing tank and increasing the process water useful life. To achieve this, treatment in closed loop to prevent MPV cross contamination was proposed.
Ozone is one of the most powerful common oxidizing agents and its decomposition leaves no residues. O3 is very effective in destroying microorganisms by the progressive oxidation of vital cell components, preventing microbial growth, either in Gram+ and Gram – bacteria, as well as spores and vegetative cells. A set of experiments were conducted at laboratory scale to get an estimation about the dose of O3 and the O3-water contact time, needed to reach an effective removal of the contaminants previously detected in the washing industrial water (micro-organisms and pesticides).The methodology followed is shown in the attached pdf figure 1: General methodology to validate the use of O3 and O3+UV as water regeneration treatment.
Mesophiliic bacteria (5.9x106 cfu/mL) and ortophenilphenol (5 ppb) were added to the industrial washing water. Almost total removal of microorganisms (6 log reduction) and pesticides was obtained using 0.06 g O3 and UV dose of 60 mj/cm2 during 2.5 min of duration treatment. Subsequently, this treatment was tested at semi-industrial application (pilot plant scale).
Results and applications:
In order to assess the effectiveness of the washing water treatment proposed (O3/UV), a set of pilot plant trials were carried out to scale down the corresponding industrial washing process. A washing machine pilot plant GWB-100 was employed (volume of 220 L of water, capacity for washing 100 kg vegetable/h) and 220kg of vegetable were washed. An ozone and UV irradiation system was designed and built to treat water in a closed loop.
The ozone system used in the experiments consists of an ozone water reactor (10 L) where a stream of the washing water was pumped in for its treatment with ozone. The ozone was generated with an ozone generator (10 g/h) fed with air coming from the oxygen supply system. In order to avoid vegetables alteration due to their contact with ozone, an UV lamp was placed to remove the residual O3 presents into the treated water.
See in the attached pdf figure 2a and 2b with the scheme of the pilot plant built to conduct the experiments.
A reduction of 20 % in water consumption was reached when O3/UV was used and the addition of fresh water was completely eliminated. For the chemical oxygen demand (COD) a reduction of 55% was reached. These results were obtained when the same washing ratio of water:vegetable (L/kg) were kept in both experiments and similar to the washing industrial ratio.
Using a water:vegetable ratio of 2 L/kg (smaller than the typical industrial ratio 6.37 L/kg), led to similar results of the O3/UV treatment, even when the hygienic conditions were worse. A reduction in water consumption of about 42 % was reached, while the levels of microorganisms were maintained and the pesticide content reduced (< 50 %) in the washing tank. Furthermore, the chemical oxygen demand (COD) was reduced to 35 % in the generated waste water.
Significance and benefits:
The effectiveness of the utilization of ozone/UV in the first washing step to treat the water in a closed loop has been demonstrated in a pilot plant scale. Significant high benefits are expected in water consumption reduction (20-42 %) and COD reduction (35 -55%), in industrial application.
Successful applications:
For the first industrial application, a study of the economical viability should be carried out. After scaling up the O3/UV system and after adjusting the parameters involved in the effectiveness of the industrial treatment (flow rate stream treated, dose of O3, contact time) a complete validation process should also be developed. Furthermore additional investigation should be developed to assess the effectiveness of the O3/UV treatment in other washing processes, i.e.: fruits.
References:
Susclean Deliverables 4.1 4.2 and 4.3.
Key result n°8: Optimizing cleaning and disinfection processes to reduce the use of water and chlorine – Water disinfection
Workpackage: WP4 – Optimising cleaning and disinfection processes to reduce the use of water and chlorine
Research aims and background:
The main objectives were: (i) to install NEOW technology at an industrial site of salad processing; (ii) to measure and validate NEOW as water disinfectant and its effect in water quality; (iii) to compare NEOW suitability as an alternative to sodium hypochlorite concerning water disinfection to wash salads reducing the free chlorine concentration; (iii) to compare organoleptic properties of salad washed with NEOW over the product shelf. In order to evaluate the water quality after treatment with NEOW, samples were collected at Vitacress from the washing and sanitizing tanks. The microbial load reduction and population in water after chlorine from NaOCl (from 60 to 90 ppm) and NEOW (29 and 40 ppm) was quantified and characterized.
Neutral Electrolyzed Oxidizing Water (NEOW) was obtained by electro dialysis of a diluted salt solution. This electro dialysis results in two components: at the anode side, an acid solution consisting of oxygen gas, chlorine gas, hypochlorite ion, hypochlorous acid and hydrochloric acid; at the cathode side, a basic solution consisting of hydrogen gas and sodium hydroxide.
The mixture of both solutions results in a neutral solution with bactericidal effect with high oxidation-reduction potential, chlorine being released in a more stable state. Due to this fact, the free chlorine concentration from NEOW needed to achieve the same microbial reduction is less to the one applied when traditional NaOCl solutions are used.
The production and laboratorial application of NEOW have been described in previous Deliverables (D3.1 and D3.2). This product was selected as a promising alternative technology to be tested at larger scales (pilot-plant and industrial plant). Some tests were made at laboratorial scale to find optimal solutions for the application of NEOW, alone or together with the traditional chorine addition method (described in D4.2). The industrial partner Vitacress selected NEOW for trials at the production plant.
Results and applications:
Overall, Streptococcci, Lactobacilli, and, Enterobacteriaceae were the major microorganism contaminants of the water at Vitacress. These bacteria were also the more persistent after water disinfection on the sanitizing tank. Results of population characterization showed that the water disinfection process is very efficient, allowing microbial load reductions in the worst case of 1 log and in the best case a total microbial load reduction, no matter the product tested (NaOCl or NEOW). NEOW showed similar efficiencies, in reducing the total mesophilic counts, as the traditional chlorine, with the advantage of the free chlorine concentration of NEOW (29 ppm) being lower than the concentration of chlorine of traditional NaOCl (60-90 ppm). Free chlorine generated by NEOW is a good alternative to NaClO and meets the objective of reducing free chlorine doses.
The obtained 1 to 2 log reduction in the decontamination of Vitacress ready-to-eat salads is typical of this industry and Vitacress intends to select NEOW as a disinfection method in the salad sanitizing tank.
Significance and benefits:
In the future, besides the clear reduction in chlorine dosage, a reduction in water consumption at Vitacress is also expected to be attained. In order to implement this technique, a continuous chlorine (from NEOW) dosing system will be adopted, since the same water can be efficiently used for 4 to 5 days. Also, cost savings in electricity for chilling the washing tank water and savings on water discharge will also be explored. In support of the adoption of this selected technology, the use of NEOW complies with the biocidal EU Regulations of 528/2012 (European Commission, 2012) due for introduction in the near future.
Successful applications:
NEOW could also be applied in other industries where water contamination occurs.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
European Commission, 2012. EU Regulations of 528/2012 Regulation (EU) No 528/2012 of the European Parliament and of the council of 22 may 2012 concerning the making available on the market and use of biocidal products.
SUSCLEAN D3.1 – Specification of applicable methods (2014).
SUSCLEAN D3.2 – Impact of alternative techniques on hygiene (2014).
SUSCLEAN D4.2 – Proposition integrating the reduction of waste water and chlorine consumption and alternative (2014).
SUSCLEAN D4.3 - Final proposition integrating the reduction of wastewater and chlorine consumption, and alternative techniques
Key result n°9: LCA modelling for the decontamination and sanitation operations
Workpackage: WP5 - Environmental assessment and best practices integration
Research aims and background:
One of the main objectives of SUSCLEAN was to contribute to the development and implementation of a new generation of environment-friendly equipment sanitation and food product decontamination technologies. Despite the consumption of chlorine and water which were the two main environmental parameters to be evaluated, the environmental impact of technologies spreads out along every stage of their life cycle, from the extraction and transformation of the raw materials, to the use stage, until the final disposal of waste back to the environment. For this reason, a life cycle perspective is required when assessing the performance of technologies. Life Cycle Assessment (LCA) is a well-established methodology normally used to assess and compare the environmental impact of products, but it has also been used to assess environmental impact of technologies.
SUSCLEAN has used the Life Cycle Assessment (LCA) methodology to evaluate the environmental performance of the new techniques aimed to reduce the consumption of water and chlorine in the decontamination and sanitation operations at MPV processing plants.
The comparative life cycle assessment requires the definition of consistent material/energy flow models for both processes, including within the boundaries of the studied systems all upward, core and downward activities related to the MPV production, as the use and disposal of materials, energy and wastes. To enable a wholesome and consistent comparison between the benchmark process and the promising alternative techniques the system boundaries have to include all processes involved in the use of these technologies.
Results and applications:
Material/energy flow net models of the benchmark sanitation and decontamination have been created. The modular structure enables a precise allocation of ecological expenditures either to the different substances (e.g. potable water, sodium hypochlorite, etc.) or specific process steps (e.g. intermediate rinsing, wastewater treatment, etc.). Furthermore, the model structure enables an easy implementation of the alternative techniques by simply exchanging one single transition which is specific for the considered technique, e.g. the preparation of sodium hypochlorite for the benchmark in comparison to the generation of NEOW as one of the promising alternative techniques. This way a comparison within consistent system boundaries can be achieved since all other aspects are being kept constant.
Adequate boundaries of the systems have been defined for a consistent LCA comparison of each technique (See figure 3 in the attached pdf, the boundaries for sanitation system).
The inventory data for developing the LCA of the core processes come from the inventory data from Vitacress installation, the experimental work carried out in SUSCLEAN project, peer-reviewed literature and sectorial reports and the commercial data bases as GaBi and Ecoinvent v2.1.
The environmental assessment is performed according to the ISO standards on LCA (ISO 14040) and the main steps described in ISO 14044.
The LCA studies have been carried out using the two LCA tools used by the partners involved: umberto® (TUBS) and GaBi® (AINIA).
Significance and benefits:
The definition of consistent material/energy flow models for both equipment sanitation and decontamination of MPV processes has enabled the environmental assessment of the most promising techniques (NEOW, O3/UV, PEF) but also will enable in the future the assessment of new techniques.
Successful applications:
LCA methodology has been successfully used to evaluate the environmental performance of the new techniques aimed to reduce the consumption of water and chlorine in the decontamination and sanitation operations at MPV processing plants.
The modular structure of the material/energy flow models developed for the benchmark sanitation and decontamination processes could be used for further assessments of new alternative techniques.
References:
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
Alfredo Rodrigo, Mandy Wesche, Irene Llorca and Stephan Scholl. 2014. Environmental assessment of new decontamination and sanitation techniques for fresh-cut products-SUSCLEAN Project. Fouling & Cleaning in Food Processing. Green Cleaning University of Cambridge. 82-88.
Deliverable D5.1 Assessment of techniques and strategies as BAT
Deliverable D5.2 Inventory analysis of environmental benefits for emerging techniques and strategies.
André Paschetag. 2014. Ökobilanzielle Bewertung des Reinigungsverfahrens einer Produktionsanlage von "Fresh-Cut Food"-Produkten. Diploma thesis. Institute for Chemical and Thermal Process Engineering, TU Braunschweig.
Key result n°10: Environmental assessment of NEOW as alternative decontamination technique
Workpackage: WP5 - Environmental assessment and best practices integration
Research aims and background:
The amount of water and chemical detergents used for washing, cleaning and disinfection in the MPV industries as well as the toxicity of the chemical agents are key indicators of environmental performance in this sector. The most widely used disinfectants in MPV industries are chlorine-based compounds despite their potential environmental and health risks with respect to the possible formation of carcinogenic cleaning-by-products (CBP), e.g. trihalomethanes [Gil et al. 2009, Ölmez and Kretschmar 2009, Gray 2014]. For this reason, chlorine is on the list of toxic substances that the EU is aiming to reduce in the sector of the food, drink and milk industries (FDM) [Regulation (EC) 166/2006, E-PRTR]. Within the SUSCLEAN project new disinfection technologies and strategies are under development to reduce the consumption of water and chemicals and identify the most sustainable alternative technique. A life cycle assessment (LCA) approach together with a multi-criteria assessment have been chosen in the project to evaluate the environmental performance and generate environmental key parameters.
Results and applications:
In the initial multi-criteria assessment approach, a holistic evaluation of technical, economic and ecological aspects has been performed and the most promising techniques for decontamination, sanitation and water treatment have been identified. In the case of decontamination the neutral electrolyzed oxidizing water (NEOW) has been determined as the most promising alternative technique.
As basis for the evaluation of the ecological performance of alternative techniques, a decontamination and sanitation process from a typical production plant in the MPV industry have been defined as benchmark. Consistent system boundaries for all techniques have been defined for the LCA to enable a reliable comparison between the different alternative techniques and the established benchmark in regards to their environmental performance. Detailed dataset from the project partners responsible for the lab, pilot plant and industrial scale tests builds the basis for the LCA.
The LCA has been carried out with material flow net modelling tools. The created models enable an easy comparison of alternative techniques and the possibility to rapidly implement new data. Furthermore, sensitivity and focus analyses have been conducted to identify the ecologically most critical substances or process steps of the investigated technique and thus give recommendations for potentials of improvement to the other WP.
On lab scale NEOW demonstrates roughly the same ecological performance as the benchmark decontamination technique with NaOCl while offering an at least equal antimicrobial activity, less hazardous residues in the waste water and easier measurement and control possibilities. The most critical process parameters from an environmental perspective are the salt input and electrical energy consumption of the NEOW generator.
On industrial scale NEOW had a worse ecological performance than the benchmark processes due to the yet unoptimized state of the NEOW generator. The environmentally most critical parameters were still the salt input as well as the electrical energy consumption.
Significance and benefits:
The integration of ecological considerations in an early stage of the design process for new disinfection techniques and strategies in the MPV industry enables the identification of the ecologically most beneficial alternatives throughout the design phase. It was shown, that it is possible to utilize consumption data from different scales for an ecological assessment of a process with a suitable material flow net model.
Successful applications:
NEOW has shown good hygienic performance results at lab scale and it had low effects on salad quality. NEOW is expected to achieve a higher level of protection of the environment in comparison to chlorine based disinfection techniques but needs to be further optimized in regards to process parameters and has to be validated at industrial scale.
References
References to the SUSCLEAN related publication(s) and SUSCLEAN deliverable(s):
Gil, M. I., et al. 2009. Fresh-cut product sanitation and wash water disinfection: Problems and solutions. International journal of food microbiology. 134. (1): 37-45.
Gray, N.F. 2014. Chapter Thirty-One - Free and Combined Chlorine. Microbiology of Waterborne Diseases Microbiological Aspects and Risks (Second Edition). Academic Press: 571-590.
Ölmez, H. Kretzschmar, U. 2009. Potential alternative disinfection methods for organic fresh-cut industry for minimizing water consumption and environmental impact. LWT-Food Science and Technology. 42 (3). 686-693.
REGULATION (EC) No 166/2006 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 18 January 2006 concerning the establishment of a European Pollutant Release and Transfer Register and amending Council Directives 91/689/EEC and 96/61/EC
Key result n°11: Environmental assessment of the reuse of water at washing step after a O3/UV treatment
Workpackage: WP5 - Environmental assessment and best practices integration
Research aims and background:
The washing step is one of the main water consuming steps in the processing of fresh cut vegetables. In this step (see in the attached pdf figure 4: Pilot plant: washing step with a loop to treat a stream of washing water with O3/UV), salad is transported to a first washing tank or to a shower line where vegetables are washed with drinking water to remove debris, and then optionally directed to the disinfection tank. There is a continuous input of drinking water to maintain the quality of the washing water in a way to prevent the cross contamination along the processing period. The consumption at this stage can round between 3-6 m3 drinking water /h, or even more than 12 m3/h when the disinfection step with chlorine does not exist, as it happens in some EU countries.
Reuse of water at this step was identified as one of the best strategies to reduce significantly the water consumption in MPV plants. As described in another key result, the reuse of water at washing step after a O3/UV treatment allow to reduce water consumption in around 20%, while maintaining the hygienic level of the washing water.
However, the environmental impact of technologies spreads out along every stage of their life cycle, from the extraction and transformation of the raw materials and energy, to the use stage, until the final disposal of waste back to the environment. For this reason, a life cycle perspective is required when assessing the performance of technologies.
This report present the results of the LCA of the O3/UV technique in comparison to the standard technique based on the continuous use of fresh water.
Results and applications:
An attributional LCA environmental assessment was performed according to the ISO standards. LCI is based on on the results of the pilot plant scale tests performed in AINIA within the WP4 of the SUSCLEAN project, literature sources and commercial databases (PE International 2006), and Ecoinvent v2.1 database). CML 2001 method has been used for the environmental assessment. The functional unit for decontamination process is to “achieve the required level of decontamination in 1 kg of clean lettuce or 1 kg of baby leaves”.
The reuse of water at washing step allowed to reduce the direct water use in the all decontamination process by 16% compared with the reference scenario (without water recirculation). Reuse of water after O3/UV treatment also reduces the water consumption from a life cycle point of view since less indirect water consumption (associated to the electricity production) was required for water conditioning and water cooling.
The electricity consumption is slightly lower in the case of water recirculation because the electricity needed for the O3/UV treatment is compensated by a lower electricity consumption required for water cooling and water conditioning. Also the consumption for wastewater treatment is lower due to a partial oxidation of the COD in the O3/UV treatment.
Finally, the results of the comparative LCIA for the reference decontamination technique and O3/UV technique were very similar values in all impact categories (see table 1 in the attached pdf), with slightly lower impacts for the water recirculation scenario.
Significance and benefits:
On a life cycle perspective, the reuse of water at washing step after an O3/UV treatment allowed a significant reduction on water consumption, a slightly lower energy consumption, no chemical consumption, no reaction by-products and lower organic load in wastewater. Furthermore, environmental performance based on the environmental indicators (CML 2001) was slightly better for the O3/UV technique compared with the conventional technique.
However, the reuse of water at washing step after an O3/UV treatment should be tested at industrial scale to confirm the results obtained.
Successful applications:
The reuse of water at washing step after an O3/UV treatment could be also investigated to be applied on the washing step of other vegetables and fruits. A complete LCA is required for assessing the overall environmental performance of the technique from a life cycle perspective.
References:
Alfredo Rodrigo, Mandy Wesche, Irene Llorca and Stephan Scholl. 2014. Environmental assessment of new decontamination and sanitation techniques for fresh-cut products-SUSCLEAN Project. Fouling & Cleaning in Food Processing. Green Cleaning University of Cambridge. 82-88.
Deliverable D4.3 Final proposition integrating the reduction of waste water and chlorine consumption, and alternative techniques.
Deliverable D6.6 Recommendations to the IPPC Guidelines for cleaning-suited equipment.
Deliverable D5.2. Inventory analysis of environmental benefits for emerging techniques and strategies.
Potential Impact:
Potential impacts
The European added value of the project lies in increasing the innovation capacity of the equipment manufacturing industry. SUSCLEAN has proposed hygienically enhanced MPV processing equipment integrating innovative sanitation techniques, together with optimised and alternative decontamination techniques, for use along the supply chain.
The innovations will target food safety and quality improvements and could be listed as follows:
o Alternative chemical and physical procedures for product washing operations reducing both wastewater and chlorine,
o Alternative chemical sanitation techniques reducing the use of chlorine,
o Equipment design principles to facilitate cleaning and disinfection and to be able to induce new environmentally friendly sanitising procedures,
o Rapid microbiological diagnostic techniques potentially allowing positive release of MPV products and helping decision makers to change to alternative decontamination strategies.
The work on characterising biofilm development and cross-contamination to food products, together with biofilm sanitising strategies will be of interest to other food industry sectors and other industries concerned in which biofilms pose a hygiene hazard (biotechnology, pharmacy, cosmetics).
The European added value lies in strengthening the competitiveness of the European fresh-cut food industry. Improvements in production sustainability, food safety and BAT were developed with the industrial partners involved in the consortium.
SMEs involved in the project as two equipment manufacturers (washing systems, cleaning/sanitising tools), two microbial contamination kit development companies (rapid surface contamination tools) will develop or has already developed their field of expertise, providing the MPV industry with competitive technical advantages over their major US and South American competitors.
The assessment of the cost-effectiveness and technical practicability of the new decontamination and sanitation techniques leaded the end-user project partner to integrate these innovations. Other companies of the MPV sector and in particular SMEs were informed on the potential benefits from these advances through dissemination activities (e.g. workshops, practical guides). Two other end-users (large European industries) were involved in the project as advisers increasing the impact of the novelties brought by the project.
The collaboration between academic research partners and SME research and development stakeholders in SUSCLEAN has supported some development of innovative techniques in SMEs that should increase their competitiveness as compared with multinational groups. Good examples are the two diagnostic tools companies and the equipment manufacturer.
The company image using validated environmentally friendly techniques in MPV production will be enhanced in the customer’s point of view and therefore economically beneficial for SMEs.
The European added value lies in offering improved food products of high quality and safety. SUSCLEAN was able to provide stakeholders with rapid diagnostic tools against microbial contamination allowing end-users to envisage real-time corrective actions. A predictive models taking into account the impacts of decontamination treatments and microbial dynamics to estimate the reduction in public health disease burden. Product washing and equipment sanitation conditions proposed were studied against any potential induction of any emergence of virulence and resistance of microorganisms. Guidance to improve food quality was delivered highlighting the benefits from innovative techniques.
The research has contributed to sustainability in general and, more particularly, to the EC Directive on Integrated Pollution Prevention and Control (IPPC), in terms of reducing chlorine emissions in water and decreasing water consumption rates in food industries by up to 20-50 % via a revision of the relevant best available techniques reference document(s). Upgraded BAT were proposed to the European Commission targeted to reduce chlorine, waste water and consumption thanks to alternative decontamination and sanitation solutions.
The project has resulted in numerous theoretical, technological and societal outcomes of which exploitation may lead to important fundamental and applied spin-offs. The impacts defined at the start of the project (scientific, technological and societal) were updated and are now presented (see in the attached pdf table 2: Project scientific results, table 3: Project technological results and table 4: Project societal results).
Main dissemination activities and exploitation of the results
The project website was regularly updated with dissemination materials dedicated to the general public as general project brochure into national languages, some research summary sheets to inform the industry and SMEs in their mother tongue. A webinar was available in August 2014 to inform the general public of the progresses of the project. According to the website statistics, there were 693 visitors in year 2013, 2024 visitors in the year 2014, generated total 2853 pageviews in year 2013, and 9006 pageviews in year 2014, respectively.
In parallel to a continuous dialogue with the industry, personal consultations of SMEs or through dedicated workshops were carried out. Workshops were organized in Spain, Portugal, Hungary, The Netherlands (for both Germany and The Netherlands), United Kingdom and France. The goal was the presentation of the available results and collecting stakeholder’s feedback on research needs and the applicability of the project results.
The workshop in Wageningen (Nl) merged with the last general assembly of the project was devoted to the following question: Less water and no chlorine in the fresh-cut food industries: a dream?
A discussion was initiated between the project participants of three FP7 project, Susclean, Veg-i-trade and Resfood and the industry (SMEs and Large industries) from the Netherlands and from Europe at large and with the Ministry of Health in the Netherlands. The Ministry of health agreed for the Netherlands on the necessity to update the law, followed by most of the industrials and based on the projects’ breakthrough. The main constraints to go further are public health, sustainability of the fresh-cut food industries and the European market depending on the local legislations.
The network of the National Technology Platforms of the European Technology Platform “Food For Life” was contacted and their members were asked to distribute the new knowledge. For increasing the publicity of the SUSCLEAN results and taking benefit from the synergy with the practical results of other FP6-FP7 projects in the food, diet and health area, a workshop was organized under the NTPs of ETP “Food For Life” on presenting 13 projects beside SUSCLEAN having practical results for the industry on 2nd December 2014 in Brussels.
The project results were presented at international scientific conferences as “Green Cleaning” in Cambridge (Fouling and Cleaning International Congress), EFFOST (Invited speaker in Uppsala), the 12th International Chemical and Biological Engineering Conference (Chempor in 2014), or at national events as the bi-annual ENVIFOOD meeting point conference at Madrid (Spain), at a seminar with an exhibition in the Netherlands during the Dutch Food Valley EXPO about hygienic design for the fresh cut industry, at open days for companies as Campden BRI, under BacFoodNet (COST Action FA1202), at a workshop organized at Murcia by the CSIC (Spain), at Process Net Annual Conference 2014 (Aachen, Germany, 2014), at the 2nd Annual FDG Meeting, (Braunschweig, Germany, 2014) and at Umberto User-Workshop (Hamburg, Germany, 2014).
Towards the general public in addition to information available on the website, a guide on “Safe handling of fresh fruits and vegetable at home” for consumers was prepared in August 2014 and was communicated through the CommNet network.
Three documents entitled “Code of the Best practices for Cleaning and Disinfection” and “Guideline for Cleaning Suited Equipment” and “Recommendation to the IPPC” were written. The guidelines include protocols and procedures to integrate the techniques developed and improved by SUSCLEAN in the MPV supply chain.
List of Websites:
Project public website
Relevant contact details:
SUSCLEAN Coordinator:
Thierry Benezech
Directeur de recherche INRA
UMET
Equipe PIHM
Tel : +33 3 20 43 54 12
Fax: + 33 3 20 43 54 26
E-mail : Thierry.Benezech@lille.inra.fr
SUSCLEAN Project Manager:
Léa Tourneur
INRA Transfert (IT)
3 rue de Pondichéry
75015 Paris, France
Tel : +33 (0) 1 76 21 62 06
E-mail: lea.tourneur@paris.inra.fr
