不同接种方式对食品中热损伤大肠菌群检测的比较研究

目的比较不同接种方式对食品中热损伤大肠菌群检测的影响。方法采用平板计数法、最大或然数法(most probable number,MPN)、表面涂布法、3M Petrifilm~(TM)大肠菌群测试片法、TSA+VRBG计数法等不同的接种方式对热处理食品中受损大肠菌群的检测进行了比较研究。结果平板计数法的结果均为10 CFU/g,MPN法的结果在150~460 MPN/g之间。表面涂布法、3M Petrifilm~(TM)大肠菌群测试片法、TSA+VRBG计数法的结果对数均值和标准差分别为(2.26±0.032)、(2.31±0.026)、(1.82±0.068)。统计分析发现,表面涂布法、3M Petrifilm~(TM)大肠菌群测试片法的检测结果均高于TSA+VRBG计数法,且具有极显著性意义(P0.01),而3M Petrifilm~(TM)大肠菌群测试片法的检测结果又显著高于表面涂布法(P0.05)。结论 MPN法、表面涂布法、3M Petrifilm~(TM)大肠菌群测试片法、TSA+VRBG计数法均适用于热损伤大肠菌群的检测,其中表面涂布法,特别是3M Petrifilm~(TM)大肠菌群测试片法操作简便,且复苏热损伤大肠菌群的效果好。

Comparative study of different inoculation methods for detection of heat-injured coliforms in food

Objective To compare the effects of different inoculation methods for detection of heat-injured coliforms in food. Methods A comparative study was conducted on the detection of heat-treated coliforms in food by different inoculation methods such as VRBG pouring plate, MPN technique, VRBG surface plating, 3M? Petrifilm? coliform count plate, and TSA+VRBG pouring plate. Results The results of VRBG pouring plate were all below 10 CFU/g, and the results of MPN technique were between 150-460 MPN/g. The logarithmic means and standard deviations of VRBG surface plating, 3M? Petrifilm? coliform count plate, and TSA+VRBG pouring plate were (2.26±0.032), (2.31±0.026), and (1.82±0.068). Statistical analysis showed that the test results of VRBG surface plating and 3M? Petrifilm? coliform count plate test method were all higher than those of TSA+VRBG counting method, which had significant significances (P<0.01), while the 3M? Petrifilm? coliform count plate method showed significantly higher results than the VRBG surface plating method (P<0.05). Conclusion MPN technique, VRBG surface plating method, 3M? Petrifilm? coliform count plate method, and TSA+VRBG pouring plate method are all suitable for the detection of heat-injured coliforms, among which the operation of 3M? Petrifilm? coliform count plate method is simplest and the effect of recovery of heat-injured coliforms is best.