鸡蛋中常见食源性致病菌的生长预测模型研究

Study on Predictive Modeling of Food-borne Pathogens Growth in Eggs

为快速预测鸡蛋中常见食源性致病菌的生长规律,以不同温度下贮存的不同状态的鸡蛋为试材,以Gompertz方程拟合沙门氏菌、致病性大肠杆菌和空肠弯曲杆菌在蛋内的生长曲线。结果显示,Gompertz模型能很好地模拟不同温度下三种致病菌的生长情况（R〉0.98）。蛋壳完好时接种致病菌后,在4℃低温和22-25℃常温贮存条件下,各个时间点的蛋内容物中均检测不到致病菌,但在32℃高温20 d后,都不同程度地分离到了致病菌。蛋壳轻微裂纹时,低温条件下,只有空肠弯曲杆菌接种组未分离到菌;室温条件下,致病性大肠杆菌和沙门氏菌从一开始即可侵入到蛋内,空肠弯曲杆菌在20 d时可直接检测到较多的菌量;高温条件下,致病菌在3 d后便均可快速繁殖。本模型的构建可以为常见食源性致病菌在鸡蛋内的定量风险评估提供理论依据。

To rapidly predicate food-borne bacterial growth modeling in eggs,the growth curves of salmonella,enteropathogenic Escherichia coli and campylobacter jejuni in eggs stored under different temperatures were fit by Gompertz equation. The results showed that the Gompertz modeling could commendably predict the bacterial growths under three kinds of temperatures（R0.98）. When the pathogens inoculated on the intact shells,pathogens could not be detected in the eggs stored under low temperature 4℃ and room temperature 22~25℃,but could be detected after 20 days under 32℃ high temperature. When the pathogens were inoculated on the shells with slight crack,only campylobacter jejuni could not be isolated from eggs under low temperature;under room temperature,salmonella and enteropathogenic Escherichia coli could invade in eggs at the beginning,and campylobacter jejuni could be directly detected a lot until 20 days. Under high temperature,each pathogen could rapidly grow after 3 days. This study may provide a theoretical reference for quantitative microbial risk assessment of food-borne pathogen in eggs.