2016—2018年湖南省含乳冷冻饮品生产加工过程肠杆菌科和单核细胞增生李斯特菌监测

目的 了解含乳冷冻饮品生产加工过程中肠杆菌科和单核细胞增生李斯特菌(简称单增李斯特菌)的分布,分析其污染的来源。方法 对湖南省4家含乳冷冻饮品生产企业生产加工过程各个环节的样品进行监测,采用国家标准检测方法对肠杆菌科和单增李斯特菌进行检验,利用脉冲场凝胶电泳(pulse field gel electrophoresis,PFGE)技术对分离的单增李斯特菌进行分子分型。结果 2016—2018年4家企业共监测1 132份样品。2018年66份终产品样品中肠杆菌科定量检测有超标现象(计数结果>100 CFU/g的样品有3份),同时检出2株单增李斯特菌。非食品样品中肠杆菌科检出率最高是工具类样品(48.0%)(χ²=28.440,P＜0.001),单增李斯特菌检出率最高是环境类样品(18.7%)(χ²=41.193,P＜0.001)。分离的102株单增李斯特菌共有11种PFGE带型,其中有6组分离株分别具有同源性。终产品中单增李斯特菌的污染主要来自环境定植菌株。结论 该研究对掌握含乳冷冻饮品生产加工过程肠杆菌科和单增李斯特菌的污染分布及终产品中单增李斯特菌的可能污染源有重要意义,提示企业应加强生产监管,完善生产加工过程中的卫生控制措施,防止潜在风险以保障冷冻饮品终产品的食用安全。

Surveillance of Enterobacteriaceae and Listeria monocytogenes in the production process of milk-containing frozen drinks in Hunan Province,2016-2018

Objective To characterize the occurrence of Enterobacteriaceae and Listeria monocytogenes in the production process of milk-containing frozen drinks,and to analyze the sources of contamination.Methods We monitored samples of each production process from four enterprises for milk-containing frozen drinks in Hunan Province.Enterobacteriaceae and Listeria monocytogenes were detected by the national standard method for testing.The isolates of Listeria monocytogenes were profiled by pulsed-field gel electrophoresis(PFGE).Results A total of 1,132 samples were monitored in the four enterprises from 2016 to 2018.The quantitative detection of Enterobacteriaceae in 66 end product samples in 2018 exceeded the standard(3 samples with count results>100 CFU/g),and 2 strains of Listeria monocytogenes were simultaneously detected.Among the non-food samples,the detection rate of Enterobacteriaceae in tool samples was the highest(48.0%)(χ²=28.440,P<0.001),and the detection rate of Listeria monocytogenes in environmental samples was the highest(18.7%)(χ²=41.193,P<0.001).Clonal analysis using PFGE divided 102 Listeria monocytogenes isolates into 11 patterns,and 6 patterns were homologous respectively.The contamination of Listeria monocytogenes in the end products mainly came from the environmental colonization strains.Conclusions This study is of great significance to understanding the distribution of Enterobacteriaceae and Listeria monocytogenes contamination in the production process of milk-containing frozen drinks and the potential contamination sources of Listeria monocytogenes in the end products,indicating that the enterprises should strengthen production supervision,develop better sanitary control measures of the production process,and prevent the potential risk so as to ensure the edible safety of end products of milk-containing frozen drinks.