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目的了解北京市售即食熟肉制品中单核细胞增生李斯特菌污染情况及污染来源。方法采用MPN法定量检测即食熟肉制品中的单核细胞增生李斯特菌,在对分离菌株正确鉴定的基础上,对单核细胞增生李斯特菌分离株进行脉冲场凝胶电泳分型研究。结果 197份即食熟肉制品中有14份检出单核细胞增生李斯特菌,检出率为7.11%,平均污染水平为14.31 MPN/g。其中农贸市场采集的样品单核细胞增生李斯特菌污染率(13.89%)高于熟肉专卖店(8.57%)、超市(5.75%)和饭馆(2.56%)。而超市采集样品中该菌的平均污染水平最高,为22.78 MPN/g。共发现13种单核细胞增生李斯特菌PFGE型,其中从同一农贸市场采集的样品中分离到两株同一个PFGE型别的单核细胞增生李斯特菌,提示加工环境存在单核细胞增生李斯特菌的污染或加工过程的交叉污染。结论北京市售即食熟肉制品中存在单核细胞增生李斯特菌污染,农贸市场出售产品污染状况高于超市、熟肉专卖店和饭馆。
Objective To understand the contamination status and sources of Listeria monocytogenes in ready-to-eat cooked meat products in Beijing. Methods The Listeria monocytogenes in ready-to-eat cooked meat products was quantitatively detected by MPN. Based on the correct identification of the isolated strains, the genotyping of Listeria monocytogenes isolates by pulsed-field gel electrophoresis was studied. RESULTS: Listeria monocytogenes was detected in 14 out of 197 ready-to-eat cooked meat products, with a detection rate of 7.11% and an average contamination level of 14.31 MPN / g. The sampling rate of Listeria monocytogenes (13.89%) in the farmer’s market was higher than that of the cooked meats (8.57%), the supermarket (5.75%) and the restaurant (2.56%). The average concentration of the bacteria collected in the supermarket samples was the highest, 22.78 MPN / g. Thirteen species of Listeria monocytogenes PFGE were found, of which two strains of the same PFGE-type Listeria monocytogenes were isolated from samples collected from the same farmer’s market, suggesting the presence of monocytosis in the processing environment Contamination of bacteria or cross-contamination of the process. Conclusion There is Listeria monocytogenes contamination in ready-to-eat cooked meat products in Beijing. The pollution of the products sold in the farmer’s market is higher than that of supermarkets, cooked meat stores and restaurants.