微生物不同生长期及介质参数对脉冲磁场杀菌效果的影响

利用脉冲磁场对大肠杆菌和金黄色葡萄球菌在不同生长阶段、不同介质温度及pH值的情况下进行杀菌试验，结果表明：这两种菌在对数生长期比稳定生长期和延迟生长期对磁场更敏感，两种细菌在对数生长期的后期杀菌效果均出现反弹变差的现象，反弹趋势延长至稳定生长期，并趋于平缓；介质温度越高，脉冲磁场杀菌效果越好，但该温度远低于热致死温度；介质pH值越偏中性，杀菌效果越差，pH值小于5时，杀菌效果较好。

Influence of growth stage of microorganisms and medium parameters on bactericidal effect of pulsed magnetic fields

The Escherichia coli and Staphylococcus aureus under different growth phases and different temperatures and pH values were inactivated by pulsed magnetic field. Logarithmic-phase microorganisms were more sensitive than stationary- and lag-phase microorganisms to the pulsed magnetic field. Inactivation effects of two microorganisms begin to be poorer at later period of logarithmic-phase and this rebound trend prolonged to lag-phase and tended gradually to smoothness. The rate of inactivation increaseed with the increase of temperature. The temperature was much less than the one of microorganism death caused by heating. The more pH value tended to neuter, the poorer effect of inactivation was; when pH value was less than 5, effect of inactivation was better.