Dielectric barrier discharge cold atmospheric plasma: Bacterial inactivation mechanism

Abstract

The mechanisms of inactivation against Gram‐negative bacteria (GNB) including Pseudomonas aeruginosa, Escherichia coli, and Vibrio parahaemolyticus, and Gram‐positive bacteria (GPB) involving Listeria monocytogenes and Staphylococcus aureus, by dielectric barrier discharge cold atmospheric plasma were elucidated. Both GNB and GPB were exposed to treatment with cold plasma produced from argon/oxygen mixture (90:10) as the working gas for different treatment times (1, 2.5, and 5 min). Survival counts were reduced with augmenting treatment time (TT; p < .05). All tested bacteria were not detected after TT of 5 min. There was an irreversible poration in cell wall of GNB. Meanwhile, GPB were partially shrunken after TT of 5 min. Therefore, irreversible cell wall damage, oxidation, and release of intracellular compounds including lipids, proteins and DNA were the proposed mode of action of cold plasma against GNB, whereas, oxidation and release of intracellular components played a major role in GPB. Practical applications This current research provides background knowledge about the bacterial inactivation efficacy of cold plasma, which could be used as a nonthermal technology for assuring food safety and for extending the shelf‐life of food.

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