肠炎沙门菌的温度、pH值和水分活度主参数模型的构建

为探究不同环境条件对肠炎沙门菌的生长规律影响，以液体培养基为基质，采用Baranyi模型作为一级模型，主参数模型作为二级模型。建立肠炎沙门菌在不同温度（30～42?℃）、pH值（6.6～8.0）、水分活度（0.976～0.997）环境影响下的主参数模型，基于Gamma概念，研究3?种环境的独立影响。通过决定系数评价一级模型的拟合程度、数学检验值以及拓展检验评价二级模型的有效性。结果显示：Baranyi模型可以很好地拟合肠炎沙门菌的生长（R2＞0.900）。拟合得到的主参数模型参数值分别为：Tmax?44.51?℃、Topt?34.24?℃、pHmax?8.14、pHmin?6.09、pHopt?7.55、aw（min）0.957和aw（opt）0.997，实验范围内随机组验证主参数模型得到的均方误差为2.311×10－5、偏差因子为0.963和准确因子为1.267，均在可接受范围内。本实验构建的主参数模型能有效描述肠炎沙门菌的生长状况，为食品安全保证提供良好的理论依据，可用于减少由致病菌引发的食品安全风险。

Modelling Salmonella enteritis Growth as a Function of Temperature,pH, and Water Activity with Cardinal Parameter Models

In order to investigate the effect of different environmental conditions on the growth rate of Salmonella enteritis, the bacterium was cultured in a liquid medium in this study, and the Baranyi model and cardinal parameter model (CPM were established and evaluated as primary and secondary model, respectively. Temperature (30–42 ℃), pH (6.6–8.0) and water activity (aw, 0.976–0.997) were taken as independent variables to develop the cardinal parameter models and based on the Gamma concept, the independent effects of three environmental conditions were studied. The coefficient of determination was used to evaluate the goodness of fit of the primary model and the secondary models were validated by mathematical test values. The results the experimental data were well fitted with the Baranyi model (R2 > 0.900). The estimated values of Tmax, Topt, pHmax, pHmin, pHopt, aw(min) and aw(opt) were 44.51 ℃, 34.24 ℃, 8.14, 6.09, 7.55, 0.957 and 0.997, respectively. In the external validation with random data in the experimental range investigated, acceptable mean squared error (MSE, 2.311 × 10-5), bias factor (0.963) and accuracy factor (1.267) were obtained. These results indicated that the CPM we developed could accurately predict the growth rate of S. enteritis, which could provide a valuable theoretical basis for reducing the food safety risk caused by S. enteritis.