食品微生物检验中损伤大肠杆菌的修复研究

Recovery of Sublethal Injured Escherichia coli in Food Microbiological Examination

食品微生物学检验中,大肠菌群通常作为微生物污染的指示菌,对公共卫生预防具有重要意义。试验通过60℃水浴和4℃酸环境冷藏两种方法对大肠杆菌细胞进行亚致死诱导,建立不同处理方式和时间下的大肠杆菌损伤模型,并采用化学促进法对损伤菌体进行修复实验。研究结果显示,氯化镁、丙酮酸钠及吐温80可以使亚损伤菌体在选择性培养基上不同程度地得以修复,其中0.5%吐温80与0.15%丙酮酸钠的组合修复剂对亚损伤状态大肠杆菌的修复效果较为显著,相对检出率提高了66.4%。

Coliform has been used extensively as an indicator of microbial contamination, and has an importance to public health protection in food microbiological examination. The sublethal injured Escherichia coli was induced respectively by＂ water bath at 60 ℃ and the cold preservation of acid environment at 4 ℃ .The injury model of Escherichia coli was established under different treatments and time. During the repair process of injured cells, the repair condition was developed by addition of chemical compounds. In the repair experiment of the present study, it was found that magnesium chloride, pyruvate and Tween 80 could regenerate the culturable ability of the injured cells to varying degrees in the selective, agar medium. At the lactose bile salt agar medium with 0.5% （w/v） Tween80 and 0.15% （w/v） pyruvate, the recovery rate of cold and acid stressed cells of Escherichia coli was significantly better than that of others, and the detection rate was increased by 66.4%.