嗜热脂肪芽孢杆菌热失活模型的初步建立

Preliminary establishment of thermal inactivation model of Geobacillus stearothermophilus

为了确定嗜热脂肪芽孢杆菌在100℃以下的热失活规律,本研究对107CFU·m L-1的菌液进行中心温度为70、80、90℃的热处理,根据不同时间的残存菌数量初步建立各温度条件下的热失活模型,并计算相应的致死率。结果表明,不同温度具有相同的失活规律:菌液在达到中心温度前,浓度即降低至稳定值,此时致死率分别为31.73%、40.07%、51.07%,之后随着加热时间延长至60 min,菌液浓度基本保持不变;菌液升温过程中的失活曲线均可用Exponential模型拟合,判定系数R2分别为0.982 9、0.952 9、0.994 4。

To determine the heat inactivation regularity below 100 ℃ of Geobacillus stearothermophilus the Geobacillus stearothermophilus of 107CFU·mL^-1 was heated at the center temperatures of 70,80,90 ℃,then the corresponding death rates were calculated and three inactivation models of each temperature were established based on the residual amount at different times. The results indicated the inactivation regularity experienced the same at three different temperatures. Before the bacterium sloution reached the center temperature,the concentration decreased to a nearly constant value with the corresponding death rate of 31. 73%,40. 07%,51. 07% respectively,and the concentration remained nearly constant with the heating time extending to 60 minutes. Besides,the exponential model were modeled by inactivation curves during thermal processing,and the coefficients of determination R2of70,80,90 ℃ were 0. 982 9,0. 952 9,0. 994 4 respectively.