不同温度下复溶配方乳粉中阪崎克罗诺杆菌生长状况研究

Growth of Cronobacter Sakazakii in Reconstituted Powdered Infant Formula in Different Temperatures

研究了阪崎克罗诺杆菌分别于4、15、25、37℃时在复溶婴幼儿配方乳粉中的生长增殖状况,建立数学模型,预测RPIF中C.Sakazakii生长不会对消费者产生危害的储存条件。采用平板菌落计数法测定Cronobacter.sakazakii的浓度;Gompertz和Logistic方程建立一级模型;Ratkowsky和Rosso模型作为二级模型,预测不同温度下RPIF中Cronobacter sakazakii的生长速率。结果显示除4℃外,Cronobacter Sakazakii在15、25、37℃生长良好,生长趋势符合S型曲线。基于Gompertz方程可知,不同温度下Cronobacter sakazakii的生长速率为0.23~0.81 h~(-1),且随培养温度升高而增加。结果认为将RPIF贮存于4℃时,阪崎克罗诺杆菌基本不会增殖。于15、25、37℃储存都可能因Cronobacter sakazakii增殖过快而对消费者造成危害.

Cronobacter sakazakii is a kind of life-threatening bacterium that was responsible to many infections in neonatal infants who consumed powdered infant formula(PIF)that was contaminated by this pathogen.Objective:In current study,mathematical growth model was developed to predict the growth of Cronobacter sakazakii in reconstituted PIF(RPIF)at 4℃,which represents refrigerator temperature;at 15,25℃and 37℃,which represent room temperatures in different seasons,respectively,to predict the time period that RPIF could be stored at certain temperature without detrimental impact of Cronobacter sakazakii on safe consumption.Methods:Concentration of Cronobacter sakazakii was determined using plate colony counting method.Gompertz equation and logistic equation were used as primary model;Ratkowsky model and Rosso model were used as secondary model to predict the specific growth rate of Cronobacter sakazakii in RPIF.Results:Except for 4℃,Cronobacter sakazakii grew very well at 15,25℃and 37℃,the growth tendency fitted to S-shaped growth curve.The growth rates of Cronobacter sakazakii ranged from 0.23 to 0.81 h-1 based on the equation of Gompertz,and generally increased with temperature increasing.Conclusion:The Cronobacter sakazakii in RPIF would hardly grow if it was stored in the refrigerator at 4℃,otherwise,it would be great hazards for infant and/or baby to be infected when the RPIF was stored at 15,25℃and 37℃.