冷冻损伤大肠菌群在乳糖胆盐发酵培养基生长状况

Observation on the growth of freeze-injured coliforms on the lactose bile broth medium

目的研究经-20℃冷冻损伤的大肠菌群在乳糖胆盐发酵培养基上的生长状况。方法选用大肠埃希氏菌、阴沟肠杆菌、弗劳地枸橼酸杆菌、产气克雷伯氏菌等4株大肠菌群菌株为研究菌株,经-20℃冷冻贮存不同时间后,分析在乳糖胆盐发酵培养基的生长。结果-20℃冷冻损伤大肠埃希氏菌、阴沟肠杆菌、弗劳地枸橼酸杆菌、产气克雷伯氏在菌乳糖胆盐发酵培养基生长抑制;大肠埃希氏菌、弗劳地枸橼酸杆菌、阴沟肠杆菌的损伤率大于产气克雷伯氏菌的损伤率,冷冻1d后,其损伤率高达70%以上;阴沟肠杆菌、产气克雷伯氏菌的死亡率大于大肠埃希氏菌、弗劳地枸橼酸杆菌,冷冻1d后,其死亡率均高达80%以上。结论-20℃冷冻损伤大肠菌群在常规检测中使用的乳糖胆盐发酵培养基生长抑制,提示应探索有效的检测方法,以修复冷冻损伤大肠菌群。

Objective To study the survival of freeze-injured coliforms at -20℃ on the lactose bile broth medium Methods The influence of lactose bile broth medium on the survival of four freeze-injured coliforms including Escherichia coli, Enterobacter cloacae, Citrobacter freundii and Klebsiella aerogenes at -20℃ storage was studied. Results Lactose bile broth medium affected the survival of the freeze-injured Escherichia coli, Enterobaeter cloacae, Citrobaeter freundii and Klebsiella aerogenes at -20℃. The percentage of injury varied in different types of coliforms.The freeze-injury rates of Escherichia coli, Citrobaeter freundii and Enterobacter cloacae were higher than that of Klebsiella aerogenes. The freezeinjury rates of Escherichia col, Citrobacter freundii and Enterobaeter cloacae a day after storage was over 70% .The mortalities of Enterobacter cloacae and Klebsiella aerogenes were higher than that of Escherichia coli and Citrobacter freundii.The freeze-mortality rates the four coliforms a day afer frozen storage was over 80%. Conclusions The lactose bile broth medium can inhibit the survival of the freeze-injured coliforms at -20℃.