为研究方波脉冲前沿陡度对高压脉冲电场技术(PEF)杀菌效果的影响,通过实验研究了前沿陡化的方波脉冲对金黄色葡萄球菌的杀灭效果。考察并比较了在不同电场强度、等效处理时间、电导率条件下,陡前沿方波和普通方波的杀菌效果。结果表明,脉冲电场的杀菌效果随着电场强度、溶液电导率、等效处理时间的增大而增强,且方波脉冲的上升时间对金葡菌的杀灭效果具有显著影响。上升时间为200ns的脉冲电场处理后的细菌残存率比上升时间为2邮的脉冲电场的残存率大,且前者的温升比后者小。当杀菌效果相同时,陡前沿方波脉冲所需的等效处理时间比普通方波脉冲更短。此外,陡前沿方波脉冲杀菌效果的提升并非通过改变细胞形貌结构来实现,而是直接作用于细胞内部。
In order to determine the influence of rectangular pulse's rising time on the inactivation effect of high-voltage pulsed electric field (PEF), we performed experiments of inactivating staphylococcus aureus using rectangular pulses with short rising time. With different electric field strengths, equivalent treatment times and sample electrical conductivity, the inactivation effects of rectangular pulses with or without short rising time are studied. The results showed that, the inacti- vation effect of PEF is enhanced with increasing electric field strength, electrical conductivity of solution and equivalent treatment time, while the rising time of rectangular pulses has a significant impact on the inactivation effect against sta- phylococcus aureus. The survival ratio of staphylococcus aureus after treatment by PEF with a rising time of 200 ns is bigger than that of PEF with a rising time of 2 ps, while the former PEF induces smaller temperature rise. Moreover, for the same inactivation effect, treatment using rectangular pulses with short rising time requires shorter time than treatments using common rectangular pulses. Furthermore, instead of shifting cells' morphology structure, rectangular pulses with short rising time rather work by changing the inside of cells.