常压低温等离子体对酵母菌的失活作用

Sterilizing effect of low temperature atmospheric pressure plasma on yeast

对氦气介质阻挡放电等离子体和氦气毛细管介质阻挡放电冷等离子体射流失活酵母菌的效率和机制进行了比较研究.分析比较了两种等离子体处理的菌液存活曲线和pH值的变化情况;利用扫描电子显微镜观察了菌体表面超微结构的变化.结果显示两种等离子体对酵母菌均有较强的杀灭作用,介质阻挡放电等离子体处理5 m in后可使其减少约7个数量级,而毛细管介质阻挡放电冷等离子体射流处理后可使其减少约8个数量级;同时经过两种等离子体处理后的pH值均明显下降,且毛细管介质阻挡放电冷等离子体射流处理菌液的pH下降幅度大于介质阻挡放电等离子体处理的菌液;从扫描电子显微镜的照片可以看到两种等离子体处理后的菌体均已破裂.实验结果表明毛细管介质阻挡放电冷等离子体射流失活酵母菌的效率要高于介质阻挡放电等离子体,并且杀菌机理应该与细胞破裂及pH值的变化有关.

The sterilizing effect and the inactivation mechanisms of low temperature atmospheric pressure helium plasma generated by dielectric barrier discharge and atmospheric cold plasma jet generated by capillary atmospheric dielectric barrier discharge on baker＇ s yeast were analyzed and compared. The relationship of survival number versus plasma treatment time and that of yeast pH value versus plasma treatment time using different plasmas were studied. The morphology of the yeast was observed by scanning electron microscopy. Resuits demonstrate that two kinds of plasma have strong sterilization effect on the yeast. At least a 7 log 10reduction in the survival number after being treated with plasma generated by dielectric barrier discharge and at least a 8 log 10reduction in the survival number after being treated with cold plasma jet generated by capillary atmospheric dielectric barrier discharge are realized. Simultaneously, pH value has remarkable change after two kinds of plasma treatment and it is more remarkably changed for atmospheric cold plasma jet generated by capillary atmospheric dielectric barrier discharge. The yeast treated with two kinds of plasma ruptures completely. It is demonstrated that the sterilizing effect of cold plasma jet generated by capillary atmospheric dielectric barrier discharge is stronger than that generated by dielectric barrier discharge. The inactivation mechanisms are concerned with the rupture of the yeast and the pH value change.