利用脉冲磁场设备对枯草芽孢杆菌进行杀菌试验,研究介质温度、pH和水分活度对其杀菌效果的影响.采用倾注平板计数法对杀菌结果进行检查.结果表明:低温或较高温对脉冲磁场的杀菌作用具有促进作用,酸性或碱性介质也促进了脉冲磁场的杀菌作用,水分活度越低,杀菌作用越强.采用磁场强度为3.0 T,脉冲数为30的脉冲磁场进行杀菌,介质温度为5℃时,枯草芽孢杆菌的残留率最低为19.15％；介质pH为4.5时,残留率最低为3.00％；介质水分活度为0.88时,残留率最低为3.14％.通过透射电镜观测,磁场可能破坏了枯草芽孢杆菌的细胞膜结构,而较高温度的酸性介质有可能增强破坏作用.低温或较高温、低pH、低水分活度的介质可以提高脉冲磁场的杀菌效果.%Effect of temperature, pH water aclivhy in medium on in-activation of Bacillus Subtilis by pulsed magnetic field were investigated. Pour plate counting method was used to test inactivation result. Result showed that low and higher temperature, and acidic or alkaline medium all increased the inactivation influence of pulsed magnetic field. The lower water activity, the stronger inactivation effect on Bacillus Subtilis. When magnetic field intensity was 3. 0 T and pulse number was 30, the survival rate reached to minimum value of 19. 15% , 3. 00% and 3. 14% at temperature of 5℃ , pH value of 4. 5 and water activity of 0. 88, respectively. Transmission electron microscope observation indicated that pulsed magnetic field may destroyed the cell membrane and acidic medium with higher temperature strengthened the damage. Conclusion: Medium with low or higher temperature- low pH, and low water activity has improved inactivation effect by pulsed magnetic field.
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