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

Xiaoye Lv,Jun-Hu Cheng

doi:10.3390/molecules27030640

Xiaoye Lv, Jun-Hu Cheng

Open Access

https://doi.org/10.3390/molecules27030640

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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.

Highlights

Salmonella typhimurium (S. typhimurium) is a major causative agent of foodborne illness worldwide, resulting in approximately 155,000 deaths each year [1]
With the increase in treatment time, the conductivity of S. typhimurium bacteria solution continued to rise from 25 ms/cm to 670 ms/cm, which further demonstrated that a large number of active particles were accumulated in the liquid phase during dielectric barrier discharge (DBD) plasma treatment
Cold plasma (CP) treatment destroyed the integrity of S. typhimurium cells and altered the permeability of cell membrane

Summary

Introduction

Salmonella typhimurium (S. typhimurium) is a major causative agent of foodborne illness worldwide, resulting in approximately 155,000 deaths each year [1]. The current research on food safety of S. typhimurium mainly focuses on milk, eggs and poultry meat products. With the rise of green agriculture, organic fertilizers are widely used in the cultivation of vegetables and fruits, especially for directly contacting the soil. Fruits and vegetables, such as lettuce, strawberries, cucumbers, etc., are contaminated by S. typhimurium. These fruits and vegetables are mainly eaten directly, which is more likely to lead to the contamination with S. typhimurium and threaten human health. Cold plasma (CP), as an innovative and environmentally friendly technology, shows great potential for decontamination of fresh-cut fruits and vegetables [2,3]

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