豆腐中库特氏菌生长动力学模型和货架期预测

Construction of microbial growth kinetics prediction model of kurthia in tofu and shelf life prediction

以引起豆腐腐败的特定腐败菌库特氏菌为研究对象,研究不同温度对其生长的影响,定量评价温度对豆腐货架期的影响,为货架期快速有效的估测提供有效的手段。将库特氏菌接种到豆腐表面,在4、12、20、30℃条件下贮藏,由此建立一级和二级生长动力学模型以及剩余货架期预测模型。结果表明,Gompertz函数能够很好的描述豆腐中的微生物生长动态,建立了4种温度下豆腐的微生物生长动力学模型。采用平方根模型(Belehradek)描述温度对最大比生长速率(μmax)和延滞时间(Lag)的影响,结果表明呈现良好的线性关系。用豆腐在8℃和25℃的库特氏菌实测值进行验证,偏差度(Bf)和准确度(Af)分别为1.04、1.02和1.20、1.18。获得的剩余货架期的预测模型为:SL=Lag-[(8.6-N0)/(μmax·2.718)]·{ln[-ln(7.14-N0)/(8.6–N0)]-1},用豆腐贮藏在8℃和25℃的货架期实测值验证建立的模型,预测值和实测值的相对误差分别为-3.47%和4.89%,说明建立的模型能够快速可靠的预测豆腐的微生物学品质和剩余货架期。

Kurthia is specific spoilage organism promoting the process of the spoilage of tofu.We studied the growth of kurthia at different temperatures,made quantitative of the impact of temperature on the shelf life of tofu,provided effective method for rapid and effective estimation of shelf life.The tofu was inoculated by the specific spoilage organism kurthia,then the sample was stored at 4,12,20 and 30℃.A series of experiments had been carried out to develop and validate the growth kinetics model of kurthia for predicting the microbial quality and remaining shelf life of tofu stored in different temperature.The results from microbiological behaviors analysis showed that the kinetics models of specific spoilage organism had been developed and the growth of dynamics of this organism under 4-30℃could be well described by a Gompertz type model.And four growth models were established in tofu.The temperature dependence of Kurthia kinetic parameters-μmax(maximum specific growth rate)and Lag phase were modeled using Belehradek(square root)model.The correlation coefficient showed could finely describe the influence of temperature on growth.Validation of built kinetic models was carried out by comparing with experimental development of kurthia grown on tofu at 8℃and 25℃.Bias and accuracy factors were used as comparison indices which were 1.04,1.02 and 1.20,1.18,respectively.The results derived from validation showed that the developed models could finely predict the growth kinetic of Kurthia at 4-30℃.The predicted model of shelf life was SL=Lag-[(8.6-N0)/(μmax·2.718)] ·{ln[-ln(7.14-N0)/(8.6–N0)]-1}.Basic errors between predicted shelf life and real shelf life were-3.47%和4.89%at 8℃and 25℃,respectively,it suggested microbial growth models established in our research were valuable for rapid and realistic prediction of the microbial quality and remaining shelf life of tofu stored from 4℃to 30℃.