Decontamination and Sensory Properties of Microbiologically Contaminated Fresh Fruits and Vegetables by Microwave Plasma Processed Air (PPA)

Abstract

Currently used disinfection or sanitation methods for fresh fruits and vegetables lack antimicrobial effectiveness, but are high in costs, water consumption or chemicals. One alternative could be to apply nonthermal plasma at atmospheric pressure to the described issue. The experimental set-up implements microwave plasma, which generates plasma processed air (PPA) containing manifold reactive nitrogen species-based chemical and antimicrobial compounds. Five different fresh produces were first contaminated with seven different microorganisms e.g., bacteria, yeasts and endospores followed by a treatment with PPA. The plasma was ignited for 7 s only. After a post-plasma treatment time of maximum 15 min with PPA, reduction factors of microbiological load greater than 6 log were detected. Furthermore, sensory examinations showed only little influences in texture, appearance and odor. The characteristics of plasma and its generated cocktail of chemical compounds leads to a high microbial inactivation on various specimens and offers a wide range of possible applications. Practical Applications Nonthermal atmospheric pressure plasma is a nonthermal, nontoxic and low-cost possibility to inactivate microorganisms on fresh produce surfaces. It could be used in dry and wet environments and allows a treatment of fresh food and virtually every conceivable surface in batch or inline processes along the whole value chain of food production, and could be implemented as an alternative to ozone or chlorine dioxide treatment.