The atmospheric-pressure non-thermal dielectric barrier discharge (DBD) plasma has recently emerged as an efficient decontamination method for the food safety enhancement. Thus the objective of this study was to evaluate the effectiveness of a simple DBD plasma treatment, with a relatively low-frequency power supply operating at 60 Hz, for microbial inactivation. A parametric study of operating conditions for bacterial inactivation was conducted using nutrient agar inoculated with Escherichia coli (2.28--6.28 log CFU/ml). The microbial log reduction was enhanced with increasing input power (30, 50, 70 W) and plasma exposure time (0, 1, 3, 5, 7 min). The inactivation effect was increased by decreasing inter-electrode gap (2, 1.5, 1 cm) and by reducing the initial microorganism concentration. Accordingly, a DBD plasma treatment at 50 W for 10 min could lead to complete killing of E. coli and partial inactivation of Listeria innocua on cheese (mean log reduction: 4.75 ± 0.02 and 0.72 ± 0.01, respectively). The decontamination efficacy of DBD plasma was affected by the types of microorganisms. The changes in hardness and color of cheese were unnoticeable after 10 min treatment with a power of 50 W. Overall, the results suggested that the DBD plasma can be potentially exploited to improve the food safety.

中文翻译：

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用于切片奶酪去污和质量变化的非热气氛气体等离子体

大气压非热介质阻挡放电 (DBD) 等离子体最近已成为增强食品安全的有效净化方法。因此，本研究的目的是评估简单 DBD 等离子体处理的有效性，该处理使用频率为 60 Hz 的相对低频电源，用于微生物灭活。使用接种有大肠杆菌 (2.28--6.28 log CFU/ml) 的营养琼脂进行细菌灭活操作条件的参数研究。随着输入功率（30、50、70 W）和等离子体暴露时间（0、1、3、5、7分钟）的增加，微生物对数减少得到增强。通过减小电极间间隙 (2, 1.5, 1 cm) 和降低初始微生物浓度来增加灭活效果。因此，在 50 W 下进行 DBD 等离子体处理 10 分钟可完全杀死大肠杆菌并部分灭活奶酪上的无害李斯特菌（平均对数减少：分别为 4.75 ± 0.02 和 0.72 ± 0.01）。DBD血浆的去污效果受微生物种类的影响。以 50 W 的功率处理 10 分钟后，奶酪的硬度和颜色的变化不明显。总的来说，结果表明 DBD 等离子体可用于改善食品安全。