婴儿配方粉干法加工过程肠杆菌科和克罗诺杆菌属监测

Survey of Enterobacteriaceae and Cronobacter spp. in the dry-mix process of powdered infant formula

目的了解婴儿配方粉干法加工过程中肠杆菌科和克罗诺杆菌属的分布,掌握终产品中克罗诺杆菌属的污染途径。方法对4家企业的产品相关样品(原辅料、中间产品和终产品)和环境进行监测,选择传统分离培养方法对肠杆菌科和克罗诺杆菌属进行检验,利用脉冲场凝胶电泳技术进行克罗诺杆菌属溯源研究。结果地面、空调回风口和使用后的清洁工具中肠杆菌科检出率较高,均在20%左右。产品相关样品、清洁作业区环境相关样品中克罗诺杆菌属检出率分别为2.56%(12/468)和0.27%(6/2 185),22株分离株共有13种脉冲场凝胶电泳(PFGE)带型,每个企业的指纹图谱各不相同,其中有四组分离株分别具有同源性。终产品中克罗诺杆菌属的污染主要来自原辅料,其次为环境中定植的菌株。结论该研究对掌握婴儿配方粉加工企业肠杆菌科和克罗诺杆菌属的污染分布及终产品中克罗诺杆菌属的可能污染源,制定加工过程的卫生控制措施,确保终产品的安全具有重要意义。

Objective To characterize the occurrence of Enterobacteriaceae and Cronobacter spp. in the powdered infant formula factories with dry-mix process,and study the potential contamination routes of Cronobacter spp. Methods Raw materials, intermediate products, end products, and environment samples from four factories were surveyed.Enterobacteriaceae and Cronobacter spp. were detected using traditional culture method. The isolates of Cronobacter spp.were profiled by pulsed-field gel electrophoresis（ PFGE）. Results The occurrence rate of Enterobacteriaceae was about 20% for the samples from the ground,air conditioning outlet and used cleaning tools. The occurrence rates of Cronobacter spp. were 2. 56%（ 12/468） and 0. 27%（ 6/2 185） from the product related samples and environmental samples in cleaning work area respectively. Clonal analysis using PFGE divided 22 Cronobacter spp. isolates into 13 patterns,each clone was unique to each factory and only four patterns were homologous respectively. The main source of Cronobacter spp.in end products was raw material,followed by environmental colonization strains. Conclusion It would help to get the distribution of Enterobacteriaceae and Cronobacter spp. in the powdered infant formula factories,identify the potential sources of Cronobacter spp. in the end products,develop sanitary control measures of the production process and ensure the end product safety.