Inactivation effects, kinetics and mechanisms of air-and nitrogen-based cold atmospheric plasma on Pseudomonas aeruginosa

Abstract

Cold atmospheric plasma (CAP) technology has attracted great interest in food processing as a novel microbe inactivation strategy. This study investigated the effects of CAP's inactivation on Pseudomonas aeruginosa and its kinetics under air- and nitrogen-CAP. Effects of reactive species on cell membranes were also studied to reveal the inactivation mechanism of air and nitrogen-based CAP. The results demonstrated that air-CAP had better inactivation capacity than that of nitrogen-CAP and Modified logistic and Dose-response models were suitable for depicting the inactivation actions of P. aeruginosa. Multiple factors contributed to the inactivation effect, such as damage to the cell morphology, changes in membrane permeability, destruction of intracellular ionic equilibrium and lipid peroxidation. Interestingly, damages of air and nitrogen-CAP to cell membrane may be different, indicating that plasma generated by different gases had different targets when attacking cells. Air-CAP could pose more severe destruction to cell membranes compared to nitrogen-CAP, while nitrogen-CAP would cause fragmentations of biomacromolecules. These findings provided some insights for further investigation of bacteria inactivation mechanisms.