摘要
以金黄色葡萄球菌为对象,研究磁场强度、脉冲数和样品温度对杀菌效果的影响。结果发现:随磁场强度的增加,金黄色葡萄球菌残留率总体呈下降趋势,其中磁场强度3.5T时杀菌效果最好;活菌残留率随脉冲数的增加而降低,在20个脉冲数时达到最低,之后残留率趋于稳定;温度对杀菌效果有一定的协同促进作用。研究得到了脉冲磁场杀菌的最优条件为:磁场强度3.5T、脉冲数20个、样品温度30℃,此条件下金黄色葡萄球菌残留率为7.29%。在本实验中,金黄色葡萄球菌ATCC25923的脉冲磁场杀菌效果表现出生物学窗效应:脉冲数的窗值为20;当脉冲数为20时,磁场强度的窗值IW符合如下递推关系:IW(n)=n(9-n)/4-1(n为"强度窗"的出现序次,n=1、2、3)。通过分析Gelow模型、Weibull模型和Hulsheger模型决定系数(R2)表明,Gelow模型最好地拟合了脉冲磁场作用下金黄色葡萄球菌残留率动力学变化。
The sterilization effect of pulsed magnetic field treatment on Staphylococcus aureus was examined under different levels of field intensity,pulse number and bacterial suspension temperature.As field intensity increased,the residual survival rate of Staphylococcus aureus generally tended to decrease and the best sterilization effect was observed at a filed intensity of 3.5 T.The effect of pulse number on the residual survival rate of this strain was similar to that of field intensity,and the residual survival rate of this strain reached its minimum after 20 pulses were completed,and then tended to be unchanged with increasing pulse number.Additionally,environmental temperature had a synergistic promoting effect on the inactivation of Staphylococcus aureus.The above results demonstrate that the optimal levels of field intensity,pulse number and bacterial suspension temperature for sterilizing Staphylococcus aureus were 3.5 T,20 and 30℃,respectively.The percentage of residual viable cells was 7.29% under these conditions.The sterilization of pulsed magnetic field on Staphylococcus aureus displayed a biological window effect.The window value of field intensity under 20 pulse number and 20 window value of pulse number accorded with the following recurrence formula：IW（n） = n（9-n）/4-1（n is appearing sequence of the window value of field intensity,n = 1,2 and 3）.The comparative analysis of correlation coefficients（R2） of the Gelow,the Weibull and the Hulsheger models indicates that the Gelow model is the best model describing the dynamic change of percentage of residual viable Staphylococcus aureus cells during pulsed magnetic field treatment.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2010年第21期20-23,共4页
Food Science
基金
国家"863"计划重点项目(2007AA100405)
关键词
脉冲磁场
金黄色葡萄球菌
杀菌
窗效应
动力学
pulsed magnetic field
Staphylococcus aureus
sterilization
biological window effect
dynamics model
