营养肉汤中金黄色葡萄球菌致死模型的构建

Establishment of Causing Death Modol of Staphylococcus aureus in Nutrient Broth

采用营养肉汤培养基,研究不同温度(T)、pH、水分活度(Aw)和乳链菌肽(nisin)对金黄色葡萄球菌的致死作用,构建金黄色葡萄球菌致死量的初级致死模型和次级致死模型。研究结果表明:金黄色葡萄球菌致死量随着T、pH和Aw的降低而增加,随着nisin的增加而降低;Aw与pH,nisin与pH存在明显的交互作用。初级致死模型符合Weibull模型,包括pH-Weibull模型,nisin-Weibull模型,决定系数R^2分别为0.9278,0.9849。通过二次多项式回归拟合得到的次级致死模型,决定系数R^2为0.9746。经验证,模型拟合度较高,能准确描述金黄色葡萄球菌的致死规律,并预测建模范围内金黄色葡萄球菌的致死量。

Effects of temperature,pH,Aw and nisin on inactivation of Staphylococcus aureus in nutrient broth medium were studied,respectively,and the primary and secondary model of lethal dose of S.aureus were built subsequently.Result showed that decreased temperature,pH and Aw could increase the lethal dose,whereas increased nisin concentrations could increase the lethal dose.Lethal dose of S.aureus was modeled as a function of pH and Aw,which revealed a good exponential relationship evaluated by the Weibull model with correlation coefficients of 0.914 and 0.947,respectively.The secondary model,a polynomial logistic regression equation was fitted using a stepwise method,which correlation coefficient was 0.976.The models were verified good to predict the lethal dose of S.aureus within certain limits.