常温下热鲜猪肉中沙门氏菌生长预测模型的建立

Predictive Models for Salmonella in Fresh Pork at Household Temperatures

建立了热鲜猪肉中沙门氏菌在消费者习惯放置温度下的生长模型,通过对沙门氏菌的生长预测,为安全消费热鲜猪肉提供预警技术。对无菌热鲜猪肉片表面进行沙门氏菌人工接种后,置于7℃,12℃,15℃,18℃,22℃,25℃,28℃和30℃温度下储存,根据不同的温度设置不同的时间间隔进行沙门氏菌计数,并绘制生长曲线。采用修正的Gompertz方程和Baranyi & Roberts方程对生长曲线进行一级模型拟合,以平方根方程为基础建立二级模型。通过对预测模型的可靠性比较分析,得出通过修正的Gompertz方程建立起来的预测模型偏差因子(Bf)为0.916 3,准确因子(Af)为1.092 7,均方根误差(RMSE)为0.017 9,通过Baranyi & Roberts方程建立起来的预测模型偏差因子(Bf)为0.990 2,准确因子(Af)为1.038 3,均方根误差(RMSE)为0.010 1。因此得出,在7℃~30℃的习惯放置范围内,Baranyi & Roberts方程能更好地拟合热鲜猪肉中沙门氏菌的生长曲线,基于该方程所建立的预测模型能更好地进行该环境下沙门氏菌的生长预测。

The objective of this investigation was to develop a model for predicting growth of Salmonella in fresh pork at variable household temperatures. The surfaces of fresh pork slices were inoculated with Salmonella and then were aseptically placed in homogeneous bags. Inoculated pork samples were incubated isothermally at 7 ℃, 12 ℃, 15 ℃, 18 ℃, 22 ℃, 25℃, 28℃ and 30℃ during different lengths of time, according to different incubation temperatures. Growth data of Salmonella was then collected and fitted to modified Gompertz model and Baranyi ＆ Roberts model respectively using Origin 8.0 software and DMFit. The secondary model used was based on a square root model for the effect of different temperatures on the maximum growth rate. Based on the analysis of the correlation coeffiecient （r）, bias factor （Bf）, accuracy factor （Af） and root mean square error （RMSE） of the two prediction models, Baranyi ＆ Roberts model was more reliabale. According to the verification, the Baranyi ＆ Roberts model in this study was more reliable than the modified Gompertz model, and it could predict the growth of Salmonella in the pork at the temperature from 7 ℃ to 30 ℃, effectively.