生菜中金黄色葡萄球菌生长模型的建立

Establishment of growth model of Staphylococcus aureus in lettuce

为建立生菜中金黄色葡萄球菌(Staphylococcus aureus)的生长预测模型,采用修正的Gompertz(SGompertz)模型和修正的Logistic(Slogistic)模型作为一级模型,分别拟合生菜中金黄色葡萄球菌在15℃、25℃、30℃、37℃和40℃条件下的生长情况,通过比较各模型的评价参数选择最优模型,获得最大比生长速率和迟滞期。在此基础上,采用Huang-rate模型和二次多项式模型建立二级生长模型,并对该模型进行验证。结果表明:在一级模型中,SGompertz模型对生菜中金黄色葡萄球菌生长曲线的拟合度较高。建立的Huang-rate模型和二次多项式模型分别为μ_(max)=0.021×(T-14.958)[1-e^(5.175(T-40.193))]和λ=0.02423T^(2)-1.97932T+42.12497;其R^(2)、偏差因子(B_(f))、准确因子(A_(f))分别为0.978、1.011、1.018和0.956、1.004、1.035,表明使用该模型描述温度对金黄色葡萄球菌最大比生长速率和迟滞期的影响是可信的。拟合结果显示,金黄色葡萄球菌在生菜中生长的最低温度为14.958℃,最高温度为40.193℃。

In order to establish the growth prediction model of Staphylococcus aureus in lettuce,the modified Gompertz(SGompertz)model and the modified logistic(Slogistic)model were used as the primary models to fit the growth of S.aureus in lettuce at 15℃,25℃,30℃,37℃and 40℃respectively.By comparing the evaluation parameters of each model,the optimal model was selected to obtain the maximum specific growth rate(μmax)and lag phase(λ).On this basis,the secondary growth model was established by using Huang-rate model and quadratic polynomial model,and the model was verified.The results showed that in the primary models,SGompertz model had a high fitting degree to the growth curve of S.aureus in lettuce.Huang-rate model and quadratic polynomial model wereμ_(max)=0.021×(T-14.958)[1-e^(5.175(T-40.193))]andλ=0.02423T^(2)-1.97932T+42.12497,respectively,and R^(2),deviation factor(B_(f)),accuracy factor(A_(f))were 0.978,1.011,1.018 and 0.956,1.004,1.035 respectively,indicating that it was credible to use the model to describe the effects of temperature on the maximum specific growth rate and lag period of S.aureus.The fitting results showed that the lowest temperature of S.aureus growing in lettuce was 14.958℃,and the highest temperature was 40.193℃.