In November, the research project SPLASH, which was funded by the German Federal Ministry of Food and Agriculture (BMEL), was officially brought to a close. Prior to this, the results of the project had already been presented to visitors at the KRONEN Customer Day: The twelve-month-long test phase, which used the newly developed HEWA washing machine in combination with the plasma washing process in an industrial setting, achieved positive results.

Against this background, the partners from the Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB Potsdam), the company Gartenfrisch Jung GmbH, the Leibniz Institute for Plasma Research and Technology (INP Greifswald) and KRONEN GmbH will continue to work together to scale the solution to meet various industrial requirements in the future.

The project involved the development of an innovative washing process for fresh-cut lettuce using non-thermal plasma technology. In this process, plasma-treated wash water (PTW) is used in a newly developed washing machine adapted to serve this precise purpose. The process for the hygienization of the lettuce helps to reduce the risk of packaged cut salads being contaminated with microorganisms.

Efficacy examined in a test phase lasting several months
To prove the efficacy of the process in an industrial setting, tests using PTW to process baby leaf lettuce and other types of lettuce in the HEWA washing machine developed by KRONEN were carried out over several months at the facility of the fresh produce manufacturer Gartenfrisch Jung GmbH. These tests examined the disinfection efficiency in the wash water and on the treated products, resource savings compared to other disinfection methods and the optimization of the products’ suitability for storage and transport.

Optimized in terms of hygiene and cleaning time: the HEWA washing machine
The development of the HEWA washing machine focused on achieving a hygienic design to ensure that the machine has no horizontal surfaces and thus allowing the water to optimally discharge. The washing machine can additionally be fully dismantled for easy and thorough cleaning and has therefore been optimized in terms of hygiene and a reduced cleaning time.

A process with a good antimicrobial effect
The use of the machine with plasma-treated water revealed extremely promising results, with the laboratory examination of the treated lettuce and the water samples providing evidence of a positive antimicrobial effect compared to the washing process using normal tap water. No negative effects of the treatment on the product whatsoever were detected. These results show that the project achieved its objective of developing a resource-conserving washing process using non-thermal plasma technology for disinfecting cut lettuce as gently as possible. The hygienization of the lettuce increases consumer safety by avoiding premature spoilage.

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