Evaluation of the Effects of Cold Plasma on Cell Membrane Lipids and Oxidative Injury of Salmonella typhimurium

Abstract

Salmonella typhimurium (S. typhimurium) is a major causative agent of foodborne illness worldwide. Cold plasma (CP) was used to inactivate S. typhimurium and to investigate the effect of CP on cell membrane lipids and oxidative injury of cells. Results indicated that the inactivation effect of CP on S. typhimurium was positively correlated with the treatment time and voltage. S. typhimurium was undetectable (total number of surviving colonies <2 log CFU/mL) after 5 min treatment with the voltage of 50 V. CP treatment caused damage to the cell membrane of S. typhimurium and the leakage of cell contents, and the relative content of unsaturated fatty acids in cell membrane decreased. Cell membrane lipids were oxidized; the malondialdehyde content increased from 0.219 nmol/mL to 0.658 nmol/mL; the catalase activity of S. typhimurium solution increased from 751 U/mL to 2542 U/mL; and the total superoxide dismutase activity increased from 3.076 U/mL to 4.54 U/mL, which confirmed the oxidative damage in S. typhimurium cell membrane caused by CP treatment. It was demonstrated that the potential application of plasma-mediated reactive oxygen species is suitable for destroying the structures of the cell membrane and ensuring the microbial safety of fresh food samples.