Fraunhofer Institute for Process Engineering and Packaging IVV
What precisely is the microbiological risk with minimally processed plant-based foods?
Fresh, ready-to-eat convenience products, and in particular salad mixtures and cut fruit, are a rapidly growing market segment in the food industry. Due to their fresh nature, these products are particularly susceptible to microbial spoiling. This is primarily caused by intrinsic microflora on the surface and secondary contamination during manufacturing processes. As the products are normally eaten in the raw state, pathogenic bacteria (e.g. EHEC) are a potential risk for consumers.
What can be done to improve the safety and shelf-life of plant-based foods?
Prolonging the shelf-life of foods that spoil rapidly is aided by innovative methods for the rapid identification and deactivation of pathogenic microorganisms on the surface of fresh and minimally processed plant-based foods (such as salad, melon, and shoots) in industrial production processes. These methods should allow customized treatment to increase the microbiological safety of the products.
What are our latest R&D findings on new sterilization methods?
A rapid culture-based method and database for identifying pathogens has been developed. Depending on the initial concentration of the bacteria this allows identification within 6 hours. This brings a huge time-saving compared to established methods used by industry.
In addition, the effect of physical sterilization methods (xenon flash light, gas plasma) and chemical sterilization methods (chlorine dioxide, electrolytically excited water) have been studied in detail in the laboratory and on a small pilot plant scale. This enabled up to 99% reduction of pathogens on the surface of melons, shoots, and salad. Due to its effectiveness, a plasma sterilization plant was developed for treating food in a continuous process.
As microbiological points of risks in the process chain are able to be identified and respective preventative measures taken, the project evaluated realistic threat scenarios.
What are the practical benefits of the new sterilization methods?
The project results can be used by food producers and relevant authorities to enhance the safety of foods for consumers. The methods that have been developed for the rapid identification and deactivation of pathogens enable any batches of contaminated products to be promptly removed from retailers and so microbiological risks reduced.