Guo J, Li Z, Huang K, Li Y, Wang J
College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China.
Institute of Food Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
J Appl Microbiol. 2017 Jan;122(1):87-96. doi: 10.1111/jam.13335.
Nonthermal plasma agents (reactive species and charged particles) are generally generated together. Previous studies of nonthermal plasma agents did not investigate the role of a microbial inactivation agent without interference from other agents. Consequently, the exact mechanism underlying their activity remains unclear. The present experiment was conducted to study the mechanism underlying Escherichia coli inactivation by nonthermal plasma.
The mechanism underlying E. coli inactivation by charged particles was studied using pure argon plasma. Results showed that cell wall damage owing to strong electrostatic forces did not occur during direct current (DC) plasma treatment with Ar or N . Next, the inactivation effects of excited N2∗, N2+, ozone, OH radicals, and nitric oxide were investigated using pure nitrogen plasma and air plasma. Morphological changes and cell rupture of E. coli were observed after 5 min of treatment with nonthermal plasma in air, but not with argon and nitrogen plasma treatments.
Our data demonstrate that reactive oxygen species play an essential role in the inactivation of E. coli.
A clear understanding of the mechanisms underlying nonthermal plasma's inactivation of micro-organism is essential for the practical applications of nonthermal plasma techniques.
非热等离子体介质（活性物种和带电粒子）通常是一起产生的。以往对非热等离子体介质的研究并未在不受其他介质干扰的情况下研究微生物灭活介质的作用。因此，其活性的确切机制仍不清楚。本实验旨在研究非热等离子体灭活大肠杆菌的机制。
使用纯氩等离子体研究带电粒子灭活大肠杆菌的机制。结果表明，在用氩气或氮气进行直流（DC）等离子体处理期间，未发生由于强静电力导致的细胞壁损伤。接下来，使用纯氮等离子体和空气等离子体研究激发态N2∗、N2+、臭氧、OH自由基和一氧化氮的灭活效果。在空气中用非热等离子体处理5分钟后观察到大肠杆菌的形态变化和细胞破裂，但氩气和氮气等离子体处理后未观察到。
我们的数据表明，活性氧物种在大肠杆菌的灭活中起重要作用。
清楚了解非热等离子体灭活微生物的机制对于非热等离子体技术的实际应用至关重要。
