《化妆品安全技术规范》(2015年版)耐热大肠菌群检验方法中目标菌的研究

Research on the target bacteria for thermotolerant coliform test method in "China safety and technical standards for cosmetics(2015)"

为研究《化妆品安全技术规范》(201 5年版)耐热大肠菌群检验方法的目标菌,收集常见耐热大肠菌群的埃希氏菌属、柠檬酸杆菌属、肠杆菌属和克雷伯菌属等4个属的全部54株模式菌株,其中45株为国外引进,采用16S rDNA序列分析和Vitek Compact 2细菌鉴定系统复核鉴定。根据《化妆品安全技术规范》检验方法,将(44.5±0.5)℃双倍乳糖胆盐培养基发酵产酸产气、(36±1)℃伊红美兰琼脂平板培养典型菌落特征和(44.5±0.5)℃靛基质试验阳性设为3项关键判定指标,以1.0×10~3 CFU·mL^(-1)的起始菌悬液按规范程序进行检验。研究发现,在54株模式菌中,共有4个属的10株菌可在高温下发酵乳糖生长,其中4株为粪源菌,但只有大肠埃希氏菌的3项关键判定指标为阳性。结果表明,在实验样本范围内,上述检验方法的目标菌为具耐热性能的大肠埃希氏菌。

To study the target bacteria for thermotolerant coliform test method in ＂China safety and technical standards for cosmetics （2015）＂, 54 types of strains relevant to thermotolerant coliforms were collected, including Escherichia sp., Citrobacter sp., Klebsiella sp. and Enterobacter sp., among which 45 strains were imported from abroad for the first time. All the strains were identified through 16S rDNA gene sequencing and Vitek Compact 2 analysis. According to the standard method in ＂China safety and technical standards for cosmetics （2015）＂, three key indexes of determination were chosen, i.e. double lactose bile medium at （44.5＋ 0.5） ~C, eosin-methylene blue medium at （36±1）℃, and indole reaction at （44.5±0.5）℃. The initial concentration of bacteria suspension was 1.0×10^3 CFU·mL^-1. It was found that 10 types of strains could ferment lactose at （44.5± 0.5）℃ including 4 fecal original strains, however, only Escherichia coil showed positive characteristics in all the three key indexes of determination. The results indicated that, in the investigated range of experimental samples, the target bacteria of above-mentioned method was thermotolerant Escherichia coli.