粮食加工品和肉制品中克罗诺杆菌的污染状况及致病性阪崎克罗诺杆菌生物膜形成能力研究

目的 克罗诺杆菌是重要的常见食源性致病菌,了解我国粮食加工品和肉制品中克罗诺杆菌的污染情况及致病性,为食品中该菌的防控提供理论依据。方法 本研究对黑龙江、北京、河北等八个省份的226份食品样品的克罗诺杆菌污染情况进行检测分离,对分离菌株基于重组和修复蛋白(recombination and repair protein gene, recN)基因序列进行种间鉴定,并针对阪崎克罗诺杆菌应用脉冲场凝胶电泳(Pulsed Field Gel Electrophoresis,PFGE)进行分子分型以及对生物膜形成能力进行研究。结果 所有样品中克罗诺杆菌的检出率为18.58%,其中146份粮食加工品中32份检出克罗诺杆菌(检出率21.2%),80份肉制品中有10份检出克罗诺杆菌(检出率12.5%)。种间鉴定显示,94株为阪崎克罗诺杆菌,6株为丙二酸盐克罗诺杆菌,3株为都柏林克罗诺杆菌,3株为尤尼沃斯克罗诺杆菌,9株为苏黎世克罗诺杆菌。PFGE分型结果表明,94株阪崎克罗诺杆菌可被分为49个型别。结晶紫染色实验结果表明所有阪崎克罗诺杆菌均在36 h~60 h时间范围内达到最大菌膜生产量。结论 上述八个省份粮食加工品和肉制品中存在克罗诺杆菌的污染,其中阪崎克罗诺杆菌有多种PFGE带型,且均具有生物膜形成能力,为食品安全风险评估及标准制定提供基础数据,对公众卫生和健康具有重要意义。

Study on contamination of Cronobacter spp. and biofilm formation ability of pathogenic Cronobacter sakazakii in cereal processed products and meat products

Objective Cronobacter spp. is an important common foodborne pathogen, the investigation of its pollution and pathogenicity in cereal processed products and meat products in China, would help to provide a theoretical basis for the prevention and control of Cronobacter spp. in food. Methods the Cronobacter spp. in 226 food samples from eight provinces including Heilongjiang, Beijing and Hebei were detected and isolated. The isolates were identified based on the recombination and repair protein gene (recN) gene sequence. Pulsed Field Gel Electrophoresis (PFGE) was used to classify the molecules of Cronobacter sakazakii and also to study the ability of biofilm formation. Results The detection rate of Cronobacter in all samples was 18.58%, of which 32 polluted samples (21.2%) were detected in 146 cereal processed products and 10 polluted samples (12.5%) were detected in 80 meat products. Interspecific identification showed that 94 strains were Cronobacter sakazakii, 6 were Cronobacter malonaticus, 3 were Cronobacter dublinensis, 3 were Cronobacter universalis and 9 were Cronobacter turicensis. PFGE typing showed that 94 strains of Cronobacter sakazakii could be divided into 49 molecular types and 20 clusters. All Cronobacter sakazakii reached the maximum biofilm production in the time range of 36 h ~ 60 h. Conclusion Cronobacter spp. was found to be contaminated in cereal processed products and meat products in the eight provinces mentioned above. Among them, Cronobacter sakazakii has a variety of PFGE types and biofilm formation ability, providing basic data for food safety risk assessment and standard formulation, which is of great significance to public health and wellness.