Cold Plasma-Mediated Inactivation of Spore-Forming Microorganisms: Mechanisms, Quality Attributes, and Efficiency Parameters

Abstract

Bacterial spores are a dormant and non-replicating state of bacteria, characterized by multiple layers of proteins, carbohydrates, and lipids. Spores from Bacillus and Clostridium species serve as main indicators of food safety, presenting considerable risks to consumers health. Heat sterilization is an easy and efficient technique; however, it compromises the quality and nutritional value of food. Cold plasma (CP), a developing non-thermal sterilization method, has demonstrated significant promise in food sterilization. CP offers a promising alternative, as it does not cause irreversible damage to sensory or nutritional attributes and is more cost-effective than traditional heat methods. The research explored the effects of different process parameters, primarily electrode type (direct or indirect plasma exposure), plasma power, duration of treatment, plasma-induced dosage, distance of samples between electrodes, and the plasma gas on the bacteriostatic effectiveness. Additionally, the interaction between plasma-induced reactive species and spore inactivation, as well as deterioration mechanisms, will be discussed thoroughly. CP can be utilized effectively, either independently or in combination with other methods, to enhance the efficacy of preservation techniques, thereby holding the potential to revolutionize food preservation practices significantly. Finally, a deeper insight into the relationship between spores and cold plasma is crucial for enhancing and improving cold plasma technology in the food industry.

Keywords: bacterial spore; cold plasma; inactivation mechanism; process variables.

FIGURE 1

The impact of process variables on the efficiency of cold plasma for the inactivation of spore‐forming microorganisms.

FIGURE 2

The structure of bacterial spores and the different protective layers against environmental factors.