Physical technologies for sanitization of fresh food products

Food sanitization has always been the subject of great attention from the agri-food chain, and in particular, it can be a strategic approach to reducing food waste by retarding food spoilage, which makes food unacceptable to consumers, and thus increasing shelf life. The recent emergency from SARS-CoV-2 has shown that good manufacturing practices and conventional certifications are insufficient to guarantee the product’s safety. Nowadays, the most used sanitization techniques exploit chemical solutions. Besides the obvious disadvantages in environmental sustainability, legislative limits prohibit the use of certain substances for sanitization, and the market is clearly directed towards clean labels and organic products. Innovative sanitization strategies based on cold atmospheric plasmas (CAPs) are raising interest in being an effective sanitization technology, not relying on chemicals or heat. In addition, plasma technologies can be used to deposit fungicides or beneficial microorganisms on food matrices, reducing the environmental impact of chemicals. Despite the ever-increasing number of scientific articles dealing with the subject, studies clearly correlating plasma characteristics with the effectiveness of the treatment and the effects on the organoleptic properties and overall quality of the treated foods still need to be included.

The research activities will include:

• Application of sanitization processes on cereals and legumes for human consumption via plasma; deposition of a protective nanocomposite coating containing microorganisms and/or antifungal compounds on the plasma. With this aim, bacterial strains suitable as protective agents will be selected. The effectiveness of the treatments will be evaluated both as a reduction of the superficial fungal contamination of the seeds and as the mycotoxin content (CNR).
• Selection of fresh food matrices in terms of i) food processing gaps (from Task 4.1.2.) and ii) suitability for plasma treatment; identification of target pathogenic and spoilage microbiota relevant to the selected food matrices, which will be selected in conjunction with Task 4.1.2.; mapping of plasma characteristics (power coupled to the discharge and concentration of reactive species as a function of operating conditions); verification of the sanitization efficacy of the plasma discharge for the selected fresh foods, also considering the effect on the overall food quality; optimization of the process to define the potential design of a plasma module for the treatments of fresh food products in a real case scenario (UNIBO).

• Development of an eco-friendly tool based on plasma technologies useful for sanitizing cereal grains and legumes (M24, CNR).
• Definition of a protocol for the deposition, via plasma process, of bioactive molecules or beneficial microorganisms on seed surface to protect foodstuff (M24, CNR).
• Correlation of plasma characteristics with sanitization effects on different classes of fresh foods, also in relation to the contaminating microbiota (M24, UniBO).
• Correlation of plasma characteristics with the eventual alteration of the organoleptic and overall quality properties of treated foods, also as a function of the type of food product (M24, UniBO).
• Definition of a set of optimised process parameters for plasma treatments of one (or more) fresh food products (M24, UniBO).
• Specifications and economic estimates for the realization of a plasma module implementable in a pilot scale food processing system for testing the sanitization process in a real case scenario (M36, UniBO).