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Development and implementation of a contact biocide polymer for its application as antimicrobial and anti-deposit surfaces in the food industry

Final ReportSummary - BIOSURF (Development and implementation of a contact biocide polymer for its application as antimicrobial and anti-deposit surfaces in the food industry)

The aim of the BIOSURF project is the development of antimicrobial surfaces and their assessment with regard to their biocide antimicrobial and anti-deposit characteristics. The development of anti-microbial and anti-deposit surfaces and coatings aim at preventing biofouling and lengthening processing time and thus minimise downtimes and give substantial cost benefits. Furthermore, the consumption of partially hazardous chemicals is dramatically decreased by minimising cleaning and disinfection processes. Thereof benefits not only the end-users but also humans in general and the entire environment. In order to develop antimicrobial surfaces, the consortium initially focused on the assessment and specification of the microbial and deposit characteristics being typical for food processing branches in general and for the BIOSURF end-user partners in particular. A questionnaire was developed and distributed, besides onsite probes from packaging material were investigated to determine 'target bacteria'. In order to develop antibacterial surfaces, aminofunctionalised poly(norbornene)s were synthesised and their antimicrobial efficiency tested. Besides TUGRAZ investigated alternative strategies to less labour-intensive and therefore cheaper and still efficient polymers. In a complementary approach, UDUN coated stainless steel plates with Ni-P-PTFE using an electroless plating system. The microbiological tests for the coated surfaces were carried out by UDUN. The combination of both concepts from UDUN and TUGRAZ finally led to further improved anti-deposit characteristics and could be protected as a patent. Furthermore, the development and testing of anti-deposit monitoring modules as well as the development of according protocols for the end-users was addressed. While partner Lagotec was responsible for the development of an anti-deposit monitoring module, TTZ was in charge of the sensor software development which will be required for process control and monitoring. The Deposens sensor allows the control of biofilm growth, whereas the according software Depotrend offers all necessary features to interpret and post process the obtained data. For facile installation of the sensor, guidelines were developed that offer the user short and precise instructions. Additionally, the four target bacteria constituted the basis for the development of the tailor made polymerase chain reaction (PCR) system which was used for detection and identification of bacterial species during further laboratory tests in the pilot plant. Subsequent to the achievements in the first project period, the most efficient antibacterial polymers were blended with commercially available PP. After assessing the antimicrobial efficiencies of the compounds and optimisation of the machine set-up regarding compounding, test tubes, designated for the test plants, were prepared. At TTZ pilot plant facility, two plants were designed and constructed alike. One test plant aimed at testing the coated surfaces prepared at UDUN and the sensor system under real production conditions, whereas the second one served for evaluation of the blended surfaces regarding biofilm formation in long-term measurements. At the end-user facilities, COASA prepared a pilot plant for on-site testing of anti-deposit surfaces via the sensor system. After testing phase, all components and the system as a whole were evaluated. The anti-deposit monitoring system performs very well, as cross checks revealed good coherence between the data from the sensor and conventional biofilm assessment. For long-term applications this system allows retrenchments regarding e.g. cleaning costs, but also steadiness in product quality can be monitored. Anti-deposit surfaces developed by UDUN were tested by COASA, revealing a reduced deposit after contact with several food media. This development implements a tremendous market potential as many surfaces within the food processing industry are made from stainless steel.

Project context and objectives:

The aim of the BIOSURF project was the development of antibacterial polymers for the implementation as biocide antimicrobial and anti-deposit surfaces in different applications in food industries. In order to assess the effectiveness and efficiency of the biocidic surfaces, anti-deposit and antimicrobial modules were developed. In addition, the biocide surfaced in combination with the monitoring modules are implemented, tested and optimised under real production conditions in order to achieve marketable products. So, the results from this project should strengthen the position on the market for the SME, as the obtained products should increase the state of the art in terms of increased resistance from microorganisms against chemical biocides and disinfectants; stringent legislation (at the EU and at international level); stronger competition and increasing consumer health and food safety demands.

WP 1 focused on the characterisation of microbial and deposit characteristics typical for food processing branches in general and for the partner industries in particular. The activities of the BIOSURF consortium within WP1 covered the assessment of the end-users' on-site conditions, including the characterisation of existing microbial populations and the specification and determination of the end-users individual biocide requirements. Based on this assessment the sensor and software requirements as e.g. accuracy and detection limit as well as monitoring requirements were defined (WP3).

The main objectives of WP2 include the accomplishment of test-polymerisations of at least 20 different amino-functionalised polymers. Furthermore, the optimal biocide material composition and blending and coating techniques are determined. Subsequently, the developed materials are tested and validated at laboratory scale. The polymers and coating are tested according to their antimicrobial activity against the four defined BIOSURF bacteria strains. Besides, alternative applications for the biocide polymer are defined.

The scope of WP3 is the development and testing of anti-deposit monitoring modules for the detection of biofilm forming microorganisms on food contact thermoplastic surfaces and coatings. Different electrical circuits are compared in terms of measurement range and sensitivity of the monitoring system for deposit detection. Additionally, monitoring and control protocols are developed for the end-users.

In WP4, the monitoring modules and surfaces are constructed on pilot-scale. Therefore, the monitoring modules are assembled and the biocide surfaces are produced by coating or blending and are assembled in pilot-plant. After finalisation of that task, the preliminary system check can be accomplished in order to correct any malfunctions prior to transportation.

WP5 deals with the testing, optimisation and evaluation of the system parameters under real conditions. Therefore, the surfaces and monitoring modules are transported and installed. After initial tests, the on-site testing and evaluation phase using the erected pilot plants starts. Finally, the overall system performance is evaluated. Besides further polymer applications are assessed.

Project results:

Work package 1

Task 1.1 Deposit and microbial characterisation of food and non-food surfaces

Extensive literature research focussing on biofilm formation and the typical loads of the different specific microorganisms likely to be found in the targeted food processing branches has been done by TTZ, Kekelit and Tugraz. Thereby, numerous publications can be found confirming that biofilms are complex habitats for a broad variety of different bacteria, fungi, algae and amoebae.

In order to assess the requirements of the end-users, TTZ has analysed the typical deposits and biofilm composition in the inner surface of closed water systems and the typical microbial load and composition of the different contact surfaces. To facilitate this procedure for the end-users, TTZ developed an exhaustive questionnaire.

KEKELIT contacted several of their clients in order to fill in the developed questionnaire and to provide typical biofilms appearing in their pipe systems. Most of the clients refused to fill in the very detailed questionnaire. Thus, it was far more time consuming to receive representative samples.

Task 1.2 Determination of the biocide surface requirements for the different applications

Based on the information gathered in task 1.1 the biocide surface requirements for the different food and non-food contact thermoplastic materials and coating was determined. This included the definition of the required antimicrobial efficiency, as well as health and safety and physicochemical and mechanical properties the different surfaces should comply with. RTD partner UDUN developed a new antimicrobial Ni-P-PTFE nanocomposite coating.

The antimicrobial efficiencies of Ni-P-PTFE coatings have been investigated using a fluorescence microscope system. It was found that PTFE content in the coatings has a significant influence on the antimicrobial efficiencies of Ni-P-PTFE coatings.

The analysis of health and safety requirements for the two contact surfaces (thermoplastic and coating) was performed, focusing on European food contact material legislation, hygienic design and good manufacturing practice guidelines.

Addressing the physicochemical and mechanical requirements, the interaction energies between the targeted microorganisms and the different surfaces (stainless steel, Ni-P-PTFE) have been calculated using the extended DLVO-theory. The effects of the surface properties of Ni-P-PTFE coatings (e.g. surface energy, surface charge etc.) on the adhesion forces of microorganisms have been investigated. Our results demonstrate that the surface energy of coatings has significant influence on microbial adhesion. In order to model the total interaction energies between bacteria and nanostructured surfaces in water, the extended DLVO theory was used.

Task 1.3 Assessment of on-site conditions and requirements at the end-users facilities

KEKELIT and COASA sent samples to TTZ in order to assess the on-site conditions and requirements at the end-user's facilities. COASA supported TTZ with several probes from their product portfolio. Three packages of cheese and one of bacon were selected.

As stated above, TTZ developed a questionnaire for end-users in order to evaluate their on-site conditions and requirements regarding their product(s), facilities, production process(es), microbiological assessment, potential biofilms and their current cleaning and disinfection processes.

Due to fact that it turned out to be quite hard to receive representative samples from end-users the consortium was facing a small time delay. As main tasks have been completed, it will have no significant impact on other tasks.

Work package 2

Task 2.1 Test polymerisation

Several polymers have been prepared by Tugraz. Eight of the most promising candidates comprised of aminofunctionalised polynorbornens were then synthesised in 2 g scale, spin-coated onto 4 x 4 cm glass slides and sent to TTZ for analysis. Besides, Kekelit and Tugraz pursued alternative strategies to develop antimicrobial polymers, which are cost saving due to easier and less laborious synthesis. Tugraz focused on the modification poly(isoprene) to introduce antimicrobial active functionalities. Commercial partner Kekelit is strongly interested in that as considerations with regard to the price of the poly(norbornene)s make alternative materials, which are used in additive amounts, very attractive. The required intense research caused a small time delay, though very promising results could be obtained, as these new materials exhibit the highest antimicrobial efficiency so far and, additionally, a cost reduction of about a factor 20 could be obtained. Overall, 18 polymers spin-coated on glass substrates were sent to TTZ for antibacterial testing.

Task 2.2 Polymer blending compositions

Tugraz together with Kekelit developed a series of compound materials. For that purpose, the most active polymer within the preliminary antimicrobial tests performed in task 2.1 was chosen and compounded with polyproplyene PP random copolymer. Intensive studies and test runs were necessary in order to find the best machine setup to guaranty the dispersion of the biocide polymer in the matrix PP-R. The test samples were then produced via injection- and compression moulding. Small polymer charges of about 1 kg polymer containing 0.5 - 3 % biocide polymer are producible homogeneously. 6 x 6 cm compound samples have been produced via injection moulding and sent to TTZ for analysis.

At the technical meeting the consortium discussed that the combination of both antimicrobial concepts from UDUN and Tugraz might lead to an improved antimicrobial activity. Such hybrid materials have been developed and tested.

Task 2.3 Polymer coating composition

At the facilities of UDUN small stainless steel plates (20 x 20 cm) are coated with a mixture of Ni-P-PTFE and a biocide polymer using an electroless plating system. The effects of electroplating conditions on the Ni-P, PTFE and pure biocide polymer contents in the coating are investigated, and accordingly optimised. UDUN developed Ni-P-PTFE- biozide polymer (BP) coatings, as it was discussed within the consortium. Tugraz supplied SM14 and SM 20, two aminofunctionalised poly(norbornene)s, which exhibit antimicrobial activity and detachment properties as shown by TTZ and UDUN. More than 70 new coatings were produced in order to find the optimised coating composition. The surface energy of these coatings was calculated, revealing significantly reduced values for the Ni-P-PTFE-BP coatings. Bacteria adhesion was tested and revealed a strongly reduced attachment on the new developed combinations Ni-P-PTFE-SM 14 and Ni-P-PTFE-SM 20. These results led to a patent disclosure, with the SME KEKELIT as a patent applicant.

Task 2.4 Laboratory testing of the preliminary surfaces

In months 1-5, TTZ supported by Tugraz developed a suitable method on the basis of the commonly used Japanese Industry Standard (JIS 2801:2000), to determine the antimicrobial activity of the thermoplastic surfaces. In preliminary tests, TTZ optimised the procedure and investigated the applicability of the testing procedure for the compound materials. A standard operation procedure for the antibacterial tests has been developed by TTZ. The antimicrobial efficiencies of the polymerised glass-plates and the polymer compounds were assessed using four types of microorganisms: Listeria monocytogenes (DSM 10290), Escherichia coli (DSM 6147), Pseudomonas fluorescens (DSM 799), Staphylococcus aureus (DSM 20600). UDUN was responsible for the microbiological tests of the stainless steel plates coated with Ni-P-PTFE, using fluorescence microscopy and the QCMD-300 system. It was demonstrated that the systems can be used to evaluate the antimicrobial efficiency of Ni-P-PTFE coatings.

In parallel to task 2.2 polymer blending composition the developed compound materials were assessed with regard to their antimicrobial and polymeric properties. TTZ tested the antimicrobial activity of the compound plates against the four defined BIOSURF test strains. It was found that the most active formulation was the 355.09.007 which was further used to develop modifications and subsequently will be assessed in the pilot plants. The alternative developed polymers exhibited a bacteriostatic activity if blended with polypropylene PP, whereas the aminofunctionalised poly(norbornene)s did not show any antibacterial activity. As required, the cytotoxicity of the poly(norbornene)s was tested. However, at that point of the project it was refrained from performing further cytotoxicity tests until an antimicrobial activity is proven under real-production conditions. Moreover, the re-use potential of PP based compound plates was tested.

Task 2.5 Alternative applications of the biocide polymer

The consortium evaluated the potential of biocide polymers in alternative applications besides food processing plants. It was decided to assess the potential of biocidic materials as food packaging foils that elongate the shelf life of food stuff. For that reason, the most active polymer compound was used to formulate seven new modifications. In order to exclude adverse influence of antimicrobial packaging on the olfactory properties of food stuff, a food approved biocide (silver Masterbatch zeolithe) was incorporated in foils that were produced on a sheet extrusion line in parallel. All foils were tested against the bacteria strain L.monocytogenes revealing an excellent antimicrobial activity. The produced foils containing the silver were subsequently used for packaging cheese samples. Assessment of the impact of this strategy on the shelf-life of cheese was performed at COASA and no significant improvement justifying the higher cost of such packaging could be identified. A second possible application emerged in the field of household sanitary. As requested in Task 2.5 'Alternative applications of biocide polymers' Kekelit carried out modifications of PMMA and ABS. These two polymers are used in the sanitary industry for bath tubes, toilet seat etc. Polymer modifications were carried out based on the modification already done in compound 355.09.007. 18 Polymer modifications were done. However, the antibacterial test results of the modifications showed no improved activity of these modifications.

Work package 3

Task 3.1 Development of anti-deposit monitoring

1) Electric circuit and sensor development

Whereas partner Lagotec was responsible for the development of an anti-deposit monitoring, TTZ was in charge for the software development which will be required for process control and monitoring. The basic parameters were discussed by Lagotec and TTZ and the software was successfully programmed at TTZ.

The aim of task 3.1 was to compare different electrical circuits in terms of measurement range and sensitivity of the monitoring system for deposit detection. Thus, different heat sources and the possibilities to change the heating power were investigated. One electrical circuit was built up with Pt100 another one with bidirectional transistors. Electrical circuits as well as probes for testing device were made. Both systems have been compared with each other to check if there is a difference in detection range and stability. The main advantage of the system with transistors is the possibility to change the heating power for different applications in deposit detection. Another advantage is the robustness and long term stability of these components by increasing temperature. A disadvantage is the more sophisticated implementation of the components into the probe. The advantage of the system with Pt100 components is that it is easier to implement the components into a measurement probe. Disadvantages are that only one measurement range can be used and that Pt100 are more influenced by fluctuating temperatures than the system with transistors.

So, another task was to implement a temperature measuring element into the probe to check external temperature fluctuations in comparison with the data sets from deposits. Automation of a cleaning procedure was also implemented. The system provides an output signal which can control a dosage pump for biocides.

2) Software development

The software development is based on the collected rough data and customer requirements. It serves as an interface between the sensor and the operator. In order to facilitate the start-up on all operating systems, the programming environment Java was chosen. So, the program works on Windows, Linux and Mac DOS operating systems and is available in a German and an English version. The software is called Depotrend and includes very helpful functions and post-processing tools that allow the operator to analyse the obtained data. It does a slope calculation of the data from the sensor to display time-dependent biofilm growth and is smoothing the values in order to generate curves which are easy to interpret. Moreover, the data of several sensors can be compiled and analysed in only one screen window.

Task 3.2 Development of microbial monitoring

TTZ decided on the components required for the development of the microbial module which are a sampling device, a DNA extraction method and tailor made PCR / qPCR systems. As for the sampling device, special tubes (coated and non-coated as well as blended and non-blended) which can easily be detached from the test plant and examined were installed in the recirculation system. These tubes therefore enable TTZ to easily obtain biofilm samples from the recirculation system without any partial deconstruction.

As further detection requires the isolation of the bacterial DNA from the biofilm, an appropriate DNA isolation method has been determined by TTZ. For assaying and selecting the appropriate isolation method out of a pool of different methods like thermal lysis, CTAB extraction and several commercially available kits, defined biofilm probes are essential.

As described above, four target organisms were defined by TTZ. These target bacteria thus constituted the basis for the development of the tailor made Polymerase chain reaction (PCR) system which will be used for detection and identification of these bacterial species during further laboratory tests with the recirculation plant. Therefore, highly specific primer sequences were defined and tested with respect to specificity and optimal annealing temperature. The defined primer sequences were tested in different PCR experiments: First the optimal annealing temperature was determined by temperature gradient PCR. Second, for elimination of any cross reactions the specificity of each primer pair was tested by using the other bacterial DNAs. The optimal annealing temperature was determined at 60 °C and it could be shown that all the tested PCR systems are highly species specific.

Task 3.3 Laboratory testing of the modules

1) Laboratory testing of the anti-deposit monitoring

Adverse as foreseen in the description of work, the consortium decided to erect two recirculation plants at the TTZ pilot plant facility, as Tugraz and Lagotec moved their facilities and an uninterrupted long-term operation would not have been possible. To test the developed anti-deposit and antimicrobial monitoring modules, a tube reactor and two identical recirculation plants were designed and constructed. The tube reactor is a sophisticated system to cultivate biofilm under stable conditions by the addition of nutrients such as glucose for a period of some weeks. As the main purpose was the investigation of the sensitivity of the sensor, this reactor was build up at Lagotec's facilities, whereas the recirculation plant was erected at the TTZ pilot plant facility and allows investigations of the sensor in a harsh environment under high pressure for a longer period as it is predominantly under real production conditions, when the recirculation media is pumped through the plant under pressure. This plant was additionally equipped with a modified Robbins device, which possesses 32 stainless steel nibs, which can be assessed individually. These nibs will be used for testing the coatings developed by UDUN.

The second plant aimed at testing the antibacterial surfaces under laboratory conditions. This recirculation plant was equipped with blended tubes fabricated by Kekelit for the assessment of antibacterial performance. As the new developed surfaces were understandably not yet food-approved at that point it was accordingly not possible to implement those materials into one of the existing food processing lines at COASA's plants, as it was originally foreseen in WP 4 and WP5. Therefore, an extra test circuit was erected at the end-user's facilities. Another crucial point in that context is the realisation of long-term tests of the anti-deposit monitoring modules without any configuration or experimental changes. Since the consortium faced a little delay at that time, it was decided to adopt the plans to the circumstances and to use the established plants for these performance stability tests. To ensure optimal mimicking conditions, the recirculation fluid, amongst other measurements, was chosen carefully. The results from the pilot plant testing of the plants at TTZ facilities are therefore an integral part of WP 5 Test, optimisation and evaluation of the system parameters under real-conditions.

2) Laboratory testing of the microbial monitoring

The completely tested and optimised microbial module enables the characterisation of biofilm probes in respect of approximate cell counts, presence or absence of tested bacterial species and the bacterial composition respectively. These data correlated with the different tested surfaces allows for rating the surfaces in respect of its properties against specific bacterial species and bacteria as a whole respectively.

As for the anti-deposit monitoring, the sampling nibs from the modified Robbins device, which provide two different (coated/uncoated) defined stainless steel surfaces in a confined space, will provide sampling material. The results of the two measurement approaches (test tubes and Modified Robbins Device) can then be compared to the results of the Deposens sensor.

Task 3.4 Development of monitoring and control protocols

Guidelines were developed, that offer the user short and precise instructions for the installation of the sensor. Moreover, this manual helps the user in accomplishing the start-up steps namely the proper installation of the transmitter and power supply as well as calibration of the sensor. In order to operate the pilot plants, blank sheets were set at the disposal of the user. This sheets features, amongst others spare fields for the monitoring module, the material and the fabrication technique used, the recirculation media, optional contamination with bacteria, temperature pressure and flow velocity, biofilm thickness as well as other remarks.

In order to guide the end-users in the implementation of the developed surfaces, monitoring and control protocols as well as the mentioned user manuals were developed. There, detailed descriptions about sensor placement, installation, calibration and maintenance and cleaning during use are given.

Work package 4

Task 4.1 Pilot-scale assembling of the anti-deposit monitoring modules

The anti-deposit modules are assembled at one pilot plant destined for anti-deposit trials at TTZ. LAGOTEC was in charge of installing the Deposens sensor, which is made of stainless steel and the optimised electrical circuit. Moreover, the plant offers the possibility to incorporate small stainless steel nibs via a modified Robbins Device for anti-deposit monitoring.

Task 4.2 Production of the coated and blended biocide surfaces

UDUN coated stainless steel nibs which are subsequently incorporated in a modified Robbins device that allows on-site monitoring in the pilot plants. By combination of the established system, which is produced by electroless plating, with aminofunctionalised poly(norbornen)s provided by Tugraz new coatings were developed. In order to evaluate the influence of the PTFE for bacteria repulsion, coatings with and without these polymer were produced and coated on the nibs. In that way, 4 different coverings (Ni-P-BP1, Ni-P-BP2, Ni-P-PTFE-BP1, Ni-P-PTFE-BP2) were coated in the stainless steel nibs and assessed at TZZ.

Additionally, UDUN treated stainless steel tubes for the end-user partner COASA. These tubes are foreseen to be incorporated in an extra test circuit and their ability to reduce organic deposits from milk was tested. The tubes were subjected to special preparations steps and subsequently treated with a special electroless treating technique. The four tubes originated from several access points and were sent to UDUN after special treatments in order to assess the deposits formed after contact with circulating hot milk for two hours, after storage of milk for two days and additionally after several standard cleaning measures. Further, UDUN treated a metal plate which was brought in contact with meat.

Kekelit in cooperation with Tugraz developed two modifications of compound 355.09.007 as this formulation showed excellent antibacterial properties in the preliminary tests. After the distribution homogeneity was improved, test species were manufactured by injection moulding, which can be easily installed in the recirculation plant by a screw connector. In the same manner, tubes were produced, whereas the antimicrobial component in this case was silver Masterbatch zeolithe. The concentrations used were 2.5 and 5 w%, as this is consistent with a final concentration that is allowed by the respective food and drug regulation. Moreover, Kekelit provided foils equipped with silver Masterbatch zeolithe in the aforementioned concentrations which will be used for field tests by COASA in order to gather experience about adverse effects of packaging materials on food media.

Task 4.3 Preliminary system check

Both pilot plants at Lagotec were put into operation, whereas Tugraz, TTZ and UDUN are responsible for the exhaustive preliminary check. After the preparing steps, the start up was performed, at which the monitoring sheets were used to document all appearing incidences. The data accumulated was stored offline on a SD memory card and can be readout be standard user programs such as MS Excel. After one week of continuous run, no noticeable incidences had occurred. The pumps were steady-going, the Deposens sensor calibrated correctly and the pipe installation did not reveal any weak points. The recirculation media was pure tab water without any additional bacteria contamination, however, as the plants were designed accordingly, no incidences using other liquids were expected. At, at that point, the consortium faced several delays, the original plan to reinstall the test plants at the end-users facilities had to be adopt and it was decided to use the readily plants further. Especially long-term tests were not considered to be feasible after a certain date therefore they were started as soon as the plants were ready.

Work package 5

Task 5.1 Transportation and installation of the surfaces and the monitoring modules

At the COASA production hall an extra test circuit was erected, where Lagotec's sensor as well as electroless treated stainless steel tubes were tested under real production conditions. In a first attempt, the sensor was installed in one of the Cabrales cheese factories. However, as this point was found to be not suitable, as daily cleaning is necessary in order to retain the production plant free from any contaminations, the sensor was additionally incorporated in the extra circuit. There, also the especially treated stainless steel pieces were incorporated. In order to pursue the efforts to find alternative applications for biocide polymers, Kekelit supplied the antibacterial polypropylene packaging foils. As the size and rigidity of the foils only allowed one method of bringing them in close contact with the cheese probes, they were cut into pieces and fitted precisely on the samples, before they were vacuum packaged.

Task 5.2 Initial tests

As it was decided to use the plants erected at TTZ facilities for further tests, no initial testing was necessary at that point, as this task has already been performed within task 4.3 Preliminary system check.

Nevertheless, initial tests were performed at COASA's newly erected test circuit. The sensor system installed suffered from a calibration problem, which made it necessary to send the sensor back to Lagotec. This, again, implied a break in the work for several weeks. During this time, the sensor position was evaluated and after the work pause, the device was installed at a new place, which was defined together with Lagotec during the final meeting. It was decided to incorporate the sensor system into the pilot plant circuit, as the original position of the sensor has to be cleaned daily in order to retain the production plant from any contaminations. The software program Depotrend was downloaded and installed to interpret the gained data.

5.3 On-site testing and optimisation

For the testing under real production conditions at TTZ, the recirculation media was chosen, the plants filled with media and inoculated with bacteria suspension. At the Kekelit pilot plant, the media used was apple juice and the biofilm was assessed qualitatively by visual examination and by thermal DNA extraction and quantified by qPCR with SYBR-Green. The first test run lasted ten weeks the formulations tested were based on the compound 355.09.007. After the test period, the tubes were cut into pieces and biofilm growth was assessed on the inner surfaces of the tubes. Up to this point the transparent tubes were monitored constantly. Subsequent to this first test run, a second one was conducted, where the influence of silver on the formation of biofilm was tested. This polymer-silver combination emerged as a promising alternative with regard to an increase in value for Kekelit's polymer tube business. This test was therefore performed beyond the project's main aim. Again, the plant was disassembled after the test period of 15 weeks. A striking fact was the intense change in the colour from transparent / white to brownish. Therefore, probes of the juice were tested at Tugraz laboratories and significant amounts of silver were detected. In both cases, the growth of biofilm was not significantly high, neither on the reference tubes nor on the test tubes in the first and second test runs. This can be rationalised by the fact, that PP features very smooth surfaces and therefore offers not ideal conditions for bacteria to settle down. At the second pilot plant, the coated nibs were subjected to short (14 days) and long-term tests (104 days). After 14 days, the visual examinations did not show any alterations in colour or degradation, however, after the long period of permanent contact with the recirculation media, the coating suffered from severe detachment. Only one coating remained uninfected. The antimicrobial test results showed a reduction of cells, however the boundary value according to the JIS was not obtained. At COASA's facilities the test plant there was used to estimate the sensor's and the specially treated stainless steel tube's potential to reduce costs for cleaning through their employment. Several test trials were carried out where the contact time with the media milk as well as cleaning measures were varied.

5.4 Overall evaluation

After the exhaustive testing period, the system was evaluated as a whole and divided in its main components. Factors contributing to this are the efficiency in preparing the biocide surfaces as well as their performance in lab scale test and under real production conditions, the accuracy and reproducibility of the anti-deposit devices and the feasibility and applicability of the test and pilot plants.

UDUN, in cooperation with Tugraz developed a new improved anti-detachment coating which was successfully protected as a patent with the end-user partner Kekelit as the patent keeper. However, in long-term measurements the stability of the coatings is still not satisfying, although UDUN has already improved this drawback. Tugraz optimised the synthesis of the antimicrobial polymers by developing more efficient and cost reducing synthetic pathways. It was estimated that a cost reduction of about a factor 20 can be reached. The most promising candidates after test polymerisations were subsequently blended with PP and, again, their antimicrobial activity evaluated. As already these preliminary lab tests revealed a reduced biocidity and, additionally, the time scale was rather limiting, it was abstained from using these materials in the pilot plants. The evaluation of the Deposens sensor system revealed a clear preference for continuous processes. As the formation of biofilm requires a certain time, it is more feasible to use the sensor in applications that are long-lasting. However, discussion with potential end-users revealed interesting new applications regarding retention of product quality, for example for food stuff that consists of fat / water emulsions. The return of invest can be, in dependence of the application be assumed as one year. The developed software Depotrend however is working properly and is ready for a market launch. It works on all operating systems and is available in English and in German.

The developed biocide monitoring modules were tested in order to gather experience about an additional value that is incorporated by equipping tubes antimicrobial. However, during the course of the tests, the growth of biofilm was not as strong as expected. At the end-users facilities, a clear tendency could be found, that the treated stainless steel tubes reduce organic deposits. Several food media was brought into close contact with the surfaces and the deposit was distinctively found to be less on the modified plates. Therefore, UDUN and COASA plan to apply for a patent application in 2011, as this development can help the end-user to save costs dramatically and additionally provides an advantage on the market as a majority of the production lines and work place in the food processing industry are made from stainless steel. Therefore, keeping the IP rights on a method to treat surfaces to that effect, that microorganism are detached and the microbiological hygiene is maintained, holds an immense market potential. An estimation was done regarding the sensor´s ability to monitor biofilm formation in respect to possible savings for cleaning agents, manpower and time, based on the findings within the onsite tests. Taking both the anti-detachment surfaces and the sensor into account, an estimation revealed a possible cost reduction of about 50 % if the cleaning can be reduced from a daily frequency to a two days repetition.

Task 5.5 Assessment of further applications

UDUN developed a highly potent electroless plating system to treat stainless steel. If the system is subsequently combined with an antimicrobial polymer provided by Tugraz, the detachment properties are even further improved. This new development was filed as a patent 'anti-biofouling Ni-P-PTFE-BP composite coating'.

As a further advantage, the treatment is unlike a coating, an alloying, therefore, the durability of the treated samples is permanent. No chemical residuals are left on the surface, only surface morphology and surface energy are changed. There is not any specificity that has to be taken into consideration when handling them. Therefore, the treatment has great potential applications in food processing, medical engineering, heat exchanger and marine industries etc to inhibit microbial and bio-deposit formation.

Stainless steel is a material widely used in many applications requiring absolute sterility. Regarding hospitality hygienic, the problem of nosocomial infections can be effectively reduced. Moreover, antimicrobial household equipment such as kitchen or bathroom sanitary features a high economical and commercial potential. Industrial applications, such as cooling or heating systems or waste water treatment plants also offer a broad field of application.

The developed sensor system can be used effectively, if some basics are considered. To safe costs of cleaning and manpower main applications are: the paper making industry, cooling towers and cooling systems, waste water treatment plants, filtration systems (membranes can be blocked by deposits), metal processing industry (coolant are up to 90 % biodegradable), sugar industry and poultry farms. But also some 'short time' applications are possible as for example in the ice cream or mayonnaise production or where other (water / fat) emulsion are produced. As discussed with different companies there are sometimes problems in production when the emulsion segregate (this induces a deposit of fat).

So not only the biofilm formation but also the product quality can be monitored by using the deposit detection system.

At COASA field tests with the aim to assess the influence of an antimicrobial additive on the organoleptic properties of food were performed. For that purpose, Kekelit produced biocide equipped foils, that were used to wrap cheese samples. A test panel then assessed taste and sensory profile after a certain period. A possible elongation of the shelf-live on the one hand and the exclusion of adverse altering effects were evaluated. The interpretation of the data revealed no clear relationship between the type of packaging used and the profiles obtained. A dependent relationship of deterioration or improvement of the organoleptic characteristics in respect to the packaging material used was not detected. So, to this point, the additional equipment of packaging foils with silver does not provide any additional value for the end-user, however, as no adverse effects were noticed, further long-term tests to define an improved shelf life behaviour absolutely advisable. Anyway, it seems to be clear for COASA that their competitiveness could not be increased by using such type of packaging, which is a very valuable result for their further strategy.

Work package 6

Task 6.1 Development of dissemination measures

In order to achieve the widest diffusion of the project results, several dissemination activities were undertaken from the consortium: 3 publications in peer reviewed journals, 6 award nominations and/or winnings, 11 articles published in popular press, 10 talks or posters at international conferences, 2 workshops, 7 videos and/or articles in the internet, 5 participations at exhibitions and 1 interview in the TV an 2 at events or workshops. The intense research work was finalised in a patent application between UDUN and Tugraz as inventors 'Beschichtung umfassend Ni-P-PTFE in Kombination mit einem polykationischen Polymer' with Kekelit as an applicant and patent holder. This is of enormous importance especially for Kekelit as the protection of intellectual properties enables them to strengthen their position on the market. Kekelit now compiles strategies to make use of this IPR. They already established contact to kitchen equipment producers in order to clarify to which extent this patent might by applicable. Also further development of new products based on that IP is in the focus of Kekelit.

Tugraz was awarded the third price of the Houska price, the highest doted industrial award in Austria. Lagotec was honoured with the Ingenieurspreis 2010 and the Hugo Wolf Innovationspreis for the developed sensor system.

Furthermore, the project was nominated for the Fast Forward Award, a Styrian economic award. In the course of these decorations, several TV clips have been produced about the project and its contributors as well as newspaper and web articles have been published.

The SMEs have distributed project flyers and information on several exhibitions, where the encounter to potential costumers can lead to new business contacts. To present the project to a broad publicity, the partners focused their endeavours on measures such as TV interviews or articles in the print media. Especially, the internet presents a beneficial platform to distribute information to a wider public.

Potential impact:

The aim of the BIOSRUF project was the development of antimicrobial and anti-deposit surfaces and the corresponding monitoring modules. There is a common need for the prevention of bacterial contaminations in the food processing industry within the European Union, as it is necessary that surfaces in contact with food stuff are free from potentially hazardous organism. Several very recent events again demonstrate the necessity and actuality of this topic. The trust of many consumers in food goods depends a lot on an ensured hygienic standard therefore tremendous losses for the food processing and packaging industries can occur, if bacterial contaminations are spread. Moreover, the risk for the customers in terms of health infections is definitely not to underestimate. Therefore, the inventions within this project pay their contribution in an improvement regarding customer safety and welfare. Especially, the filled patent 'anti-biofouling Ni-P-PTFE-BP composite coating' with UDUN and TUGRAZ as inventors and Kekelit as a patent applicant is worth to be mentioned. As Kekelit is currently in negotiations with potential end-user, their enhanced portfolio can help to promote their requests. Besides, Kekelit recently compiles strategies to make further use of this IPR.

Moreover, the intense collaboration between UDUN and COASA aiming at further improved anti-deposit surfaces from stainless steel for the food processing industry shows extremely promising results and is likely to be disclosed as an invention within this year. Alongside, both project partners declared their high interest in further cooperation.

At Tugraz facilities it could be shown, that an alternative synthetic approach could reduce costs by a factor of 20. These findings were especially sought for by industrial partner Kekelit and already led to a subsequent proposal for a project on national level in Austria.

Within the project period, Lagotec had several very successful talks to costumers, as the system is definitely ready for the market launch. The developed guidelines, that can be given as handouts depict the right installation as well as cleaning and calibrations measures for the sensor. As they are available in German and in English, a broad and international clientele can make use of the sensor system Deposens; and the according software Depotrend, that can be easily downloaded and installed.

The consortium especially contemplates public relation, as it was an abiding concern of the partners to inform a broad public about the new developments. Therefore, many attempts of the partners tend to raise the awareness of consumers. Several media were used in order to promote the utilisation of the project's outcomes, which is the implementation of the developed modules and surfaces. The partners promoted the project by the, to some extend, outstanding successfully attendance at several national awards, which, as an additional surplus value, was often accompanied by exhaustive reports in news papers and television.

Moreover, by several publications and the participation of consortium members at international conferences, the academic community was informed about the scientific achievements. Both R&D performers UDUN and Tugraz were able to submit scientific papers to peer-reviewed journals.

For anyone accessible, the project web site informs about actual activities and news as well as the aims of the project since September 2009 (see online). First the logo and subsequently the project website was designed by Maximilian Werschitz Gaphik und Text (see for details) and discussed within the consortium. The set-up of the website was done by Klopf + Neuwirth websolutions OG (see for details). The site is designed as a promotional and knowledge-sharing function, but also to raise awareness and interest in the project's results. The website is continuously updated, providing the latest information (news) and public results in the project. It features a start page including a project summary and latest news, in the next section there can be found a description of the partners with links to their homepages. The research topics give basic information about the project and the section 'News' features information of events and meetings. The homepage also contains a password protected member's area where all partners have access, can post in the forum to different topics and can up- and down-load files. The contact details of the coordinators can be found in the last section of the homepage.

Nadja Noormofidi, employed within the project as a scientific coordinator from June 2009- March 2011, could use her extraordinary experience at the field of international relations for a very successful step into industry, after finishing her PhD thesis. Both her and Eva Bradacs were honoured successful Austrian EC project coordinators. Now Miss Normofidi is employed at AT&S in Leoben, Austria, in a leading position, which was mainly offered to her due to her excellent competences and skills, she gained through the work on the project. Still on the university, she very soon recognised the importance of dissemination activities for the project and was the main responsible person for the application for several national awards and prices. It is worth mentioning, that the BIOSURF was accredited the third price of the Houske price, the highest doped industrial award in Austria. The award ceremony also offered the opportunity for the project members to develop connections to leading Austrian companies, an important chance also for industrial partner Kekelit. Additionally, the publication of reports in public news papers informed about the project and its achievements. Furthermore, the project was nominated for one more Austrian industry price, the Styrian Fast Forward Award, again accompanied by interviews, TV clips and reports in the public media. But also all the other members of the consortium were highly ambitious in disseminating activities. Lagotec was honoured with the Ingenieurspreis 2010 and the Hugo Wolf Innovationspreis for the development of the sensor system. Again, these two events allowed Lagotec to inform about their work within the project. COASA and TTZ organised several workshops, where the work and the results of the project were promoted. Additionally, reports in the public print media and interview, broadcasted on TV served for information of the publicity. An exhaustive summary of all dissemination activities within the consortium can be found in the section 1.2 Use and dissemination of the foreground.

Besides, it has to mentioned, that within the accomplishment of the project, any ethic or ethnic discriminations occurred. Regarding the employment, both women and men were chosen due to their qualification and no contribution was paid towards individual ancestry. The products and ideas developed do not favour any of both genders.

The strong synergies between university and industry had beneficial effects for both stakeholders.

The address of the project website is:

The contact details are:

Administrative manager:
Eva Bradacs
Graz University of Technology
Research and Technology House
Schloegelgasse 9/III, 8010 Graz, Austria
t: +43-316-8736026
f: +43-316-8735999

Scienific manager:
Christian Slugovc
Graz University of Technology
Institute for Chemistry and Technology of Materials
Stremayrgasse 16/I, 8010 Graz, Austria
t: +43-316-87332280
f: +43-316-87332302