搅打奶油中金黄色葡萄球菌生长预测模型的建立

Establishment of Growth Model of Staphylococcus aureus in Whipping Cream

国内外对金黄色葡萄球菌预测模型的研究集中处于一、二级模型,且乳品方面的研究又集中在牛奶,而微生物在搅打奶油的生长模型研究基本处于空白。为了填补金黄色葡萄球菌在搅打奶油中生长行为变化的空白,为金黄色葡萄球菌的风险评估提供数据支持。本文选用产A型肠毒素的金黄色葡萄球菌作为研究对象,测定了15℃、20℃、25℃、30℃、36℃下金黄色葡萄球菌在新鲜奶油中的生长曲线,运用Origin8.0软件和DMFit软件,分别使用修正的Gompertz、修正的Logistic和Baranyi三模型来拟合不同温度下的生长模型。通过比较三种模型的拟合结果,选择最适模型的生长动力学参数,选用平方根方程构建金黄色葡萄球菌最大比生长速率与温度的二级模型。结果显示,Baranyi模型对金黄色葡萄球菌的生长曲线拟合效果最好,构建的二级平方根模型拟合度较好：R2为0.92,准确因子（Af）和偏差因子（Bf）均在1左右。所构建的二级模型,能真实快速有效地预测15～36℃金黄色葡萄球菌的生长情况。

In dairy research many study about primary and secondary models of Staphylococcus aureus growth focus on the milk, but very few report related with the S. aureus growth on whipping cream. In order to well understand the S. aureus growth in whipping cream and provide data support for the risk assessment of S. aureus, a S. aureus strain produce enterotoxin A was chosen in this study and S. aureus growth curves in whipping cream at 15 ℃, 20 ℃, 25 ℃, 30 ℃ and36 ℃were obtained. The modified Gompertz, modified Logistic and Baranyi models were applied to fit the growth curves as primary models by Origin 8.0 software and DMFit software. The root-squaring model was used to fit secondary model which describing the relationship between the maximum growth rate with temperature. The results showed that the Baranyi model was the best to fit the S. aureus growth in whipping cream as primary model and the values from the Baranyi model could build the root-squaring model with R2 as 0.92, the accurate factor（Af） and the deviation factor（Bf） were around 1. This secondary model from this study can be used to predict the growth of S. aureus in whipping cream under 15 ℃～36 ℃.