Final Report Summary - DITEC (Development of novel Disinfection Technologies for Fresh Produce)
Non-thermal technologies have drawn the attention of both researchers and the fresh produce industry in recent years. Furthermore, these technologies have been also classified as environmentally friendly due to the fact that less energy and water consumption is required. Ultrasound and cold atmospheric plasma (CAP) are non-thermal technologies able to inactivate microorganisms. Moreover, the efficacy of these technologies can be enhanced by its combination with another antimicrobial process.
Marie Curie – CIG (Development of novel Disinfection Technologies for Fresh Produce- DiTec) project focused on a number of different disinfection technologies. Ultrasound and assisted-ultrasound, i.e. the combination of ultrasound with another decontamination technology, have shown to be effective against bacteria. This research evaluated the microbial reduction by different ultrasound configurations and ultrasound combined with the essential oil of oregano (EOO). Microbial challenged lettuce leaves were treated by an ultrasound system (26 kHz, 200 W) with continuous and pulsed modes at different concentrations of EOO. The structural properties of the surfaces and the histology cross sections of the treated samples were analysed by SEM and light microscopy imaging. Continuous ultrasound treatments lead to significant reductions of E. coli. Assisted-ultrasound enhanced in all cases the levels of inactivation while images reported neither structural differences nor damage among treated samples and raw samples. Assisted-ultrasound reported a synergistic effect on the inactivation of E. coli. Both treatments appeared to be harmless for the leaves’ structure.
Another objective of the DiTec was to evaluate the efficacy of ultrasound in alfalfa and mung bean sprouts when treated with ultrasound in combination with ClO2. An additive effect in the reduction of E. coli and Salmonella on inoculated alfalfa and mung bean sprouts for the combination of ultrasound and ClO2 was found. Other scientific progress in relation to non-thermal processing, included the identification the main antimicrobial species generated by a CAP (operating at 230V, 50 Hz, carried gas air) and the effect of these reactive species on the growth rate of different E. coli mutants species inoculated on butter head lettuce leaves. Finally, an ultrasound system was applied in combination with UV-C in order to treat lettuce wash water. When treatment was applied in combination, it resulted in the highest bacterial inactivation, colour reduction and reduction of organic matter after 30 minutes of treatment.
Decontamination/disinfection is the most critical processing step of fresh produce either as whole vegetables (e.g. leaves) or RTE cut salads. The current results of the DiTec are expected to increase the safety of fresh produce and extend their shelf-life, whilst maintaining or improving organoleptic characteristics. This will provide the industry with a powerful marketing advantage and is expected to amplify consumer confidence and instil a positive perception of EU fresh produce. Consequently, the market of ‘fresh convenient foods’ will be further supported (which is of importance for the EU economy) considering its significant growth in the coming years as a result of the lifestyle trends, and the increased consumer demand for products that are not only healthy, but also convenient. This will promote the replacement of chlorine by the suggested technologies and consequently it will reduce or even eliminate the potential health and environmental risks associated with the formation of carcinogenic halogenated disinfection by-products. Additionally, the probability of new outbreaks in European countries will be further limited. Consequently, SMEs will produce competitive products free from harmful chemicals and safer for human health and the environment with potential for accessing wider markets in a cost effective manner. Environmental and economic benefits will also be derived from reduced water usage, given that DiTec can be built on the development of sustainable disinfection systems that include the reuse of the water or the application of dry disinfection technologies. In addition, ultrasound and plasma technologies assessed during the activities of the DiTec project can help to decrease the environmental impact associated to the whole supply chain as they are expected to increase the shelf-life of the product and reduce the associated food waste.
A summary of the impact of the results of the project can be summarised as follows:
1. Development of sustainable alternative decontamination methodologies for fresh and fresh-cut produce with the potential to improve quality and extend the shelf-life.
2. Strengthening the competitiveness of the European fresh cut food industry and offering improved food products of high quality and safety.
3. Reducing the chlorine emissions in water and water consumption rates in food industries
4. Delivering scientific and technological knowledge to SMEs
5. Providing added value due to increasing the innovation capacity of the entire food industry, including the equipment manufacturing industry.
The past years the outcomes of the DiTec project have been communicated to the society through different means. The fellow has appeared in local media to increase public awareness of research project outcomes. Examples include presentation, articles or interviews in local science events (i.e. Science in the City), newspapers, magazines (THINK magazine) and local radio. A number of other activities related to the transfer of knowledge to the Host Institution and beyond include the coordination, co-teaching and development of a number of courses both at undergraduate and post-graduate level. For all these courses, educational tools (e.g. Virtual Learning Environment) have been used. Furthermore, the development of teaching material for an e-learning course at a postgraduate level is currently coordinated by the fellow. On that basis different modules in in the area of Microbiology, Food Safety, Food Preservation/Technology and Environmental Engineering the design and development of modules have been developed.
Marie Curie – CIG (Development of novel Disinfection Technologies for Fresh Produce- DiTec) project focused on a number of different disinfection technologies. Ultrasound and assisted-ultrasound, i.e. the combination of ultrasound with another decontamination technology, have shown to be effective against bacteria. This research evaluated the microbial reduction by different ultrasound configurations and ultrasound combined with the essential oil of oregano (EOO). Microbial challenged lettuce leaves were treated by an ultrasound system (26 kHz, 200 W) with continuous and pulsed modes at different concentrations of EOO. The structural properties of the surfaces and the histology cross sections of the treated samples were analysed by SEM and light microscopy imaging. Continuous ultrasound treatments lead to significant reductions of E. coli. Assisted-ultrasound enhanced in all cases the levels of inactivation while images reported neither structural differences nor damage among treated samples and raw samples. Assisted-ultrasound reported a synergistic effect on the inactivation of E. coli. Both treatments appeared to be harmless for the leaves’ structure.
Another objective of the DiTec was to evaluate the efficacy of ultrasound in alfalfa and mung bean sprouts when treated with ultrasound in combination with ClO2. An additive effect in the reduction of E. coli and Salmonella on inoculated alfalfa and mung bean sprouts for the combination of ultrasound and ClO2 was found. Other scientific progress in relation to non-thermal processing, included the identification the main antimicrobial species generated by a CAP (operating at 230V, 50 Hz, carried gas air) and the effect of these reactive species on the growth rate of different E. coli mutants species inoculated on butter head lettuce leaves. Finally, an ultrasound system was applied in combination with UV-C in order to treat lettuce wash water. When treatment was applied in combination, it resulted in the highest bacterial inactivation, colour reduction and reduction of organic matter after 30 minutes of treatment.
Decontamination/disinfection is the most critical processing step of fresh produce either as whole vegetables (e.g. leaves) or RTE cut salads. The current results of the DiTec are expected to increase the safety of fresh produce and extend their shelf-life, whilst maintaining or improving organoleptic characteristics. This will provide the industry with a powerful marketing advantage and is expected to amplify consumer confidence and instil a positive perception of EU fresh produce. Consequently, the market of ‘fresh convenient foods’ will be further supported (which is of importance for the EU economy) considering its significant growth in the coming years as a result of the lifestyle trends, and the increased consumer demand for products that are not only healthy, but also convenient. This will promote the replacement of chlorine by the suggested technologies and consequently it will reduce or even eliminate the potential health and environmental risks associated with the formation of carcinogenic halogenated disinfection by-products. Additionally, the probability of new outbreaks in European countries will be further limited. Consequently, SMEs will produce competitive products free from harmful chemicals and safer for human health and the environment with potential for accessing wider markets in a cost effective manner. Environmental and economic benefits will also be derived from reduced water usage, given that DiTec can be built on the development of sustainable disinfection systems that include the reuse of the water or the application of dry disinfection technologies. In addition, ultrasound and plasma technologies assessed during the activities of the DiTec project can help to decrease the environmental impact associated to the whole supply chain as they are expected to increase the shelf-life of the product and reduce the associated food waste.
A summary of the impact of the results of the project can be summarised as follows:
1. Development of sustainable alternative decontamination methodologies for fresh and fresh-cut produce with the potential to improve quality and extend the shelf-life.
2. Strengthening the competitiveness of the European fresh cut food industry and offering improved food products of high quality and safety.
3. Reducing the chlorine emissions in water and water consumption rates in food industries
4. Delivering scientific and technological knowledge to SMEs
5. Providing added value due to increasing the innovation capacity of the entire food industry, including the equipment manufacturing industry.
The past years the outcomes of the DiTec project have been communicated to the society through different means. The fellow has appeared in local media to increase public awareness of research project outcomes. Examples include presentation, articles or interviews in local science events (i.e. Science in the City), newspapers, magazines (THINK magazine) and local radio. A number of other activities related to the transfer of knowledge to the Host Institution and beyond include the coordination, co-teaching and development of a number of courses both at undergraduate and post-graduate level. For all these courses, educational tools (e.g. Virtual Learning Environment) have been used. Furthermore, the development of teaching material for an e-learning course at a postgraduate level is currently coordinated by the fellow. On that basis different modules in in the area of Microbiology, Food Safety, Food Preservation/Technology and Environmental Engineering the design and development of modules have been developed.