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目的建立单核细胞增生李斯特菌的聚合酶链式反应(PCR)检测方法,了解市售食品中单核细胞增生李斯特菌的污染情况。方法采集成都市市售生畜肉、生禽肉、熟肉制品、水产品、生食蔬菜以及其他熟食等食品样品共135份,采用李氏增菌肉汤(LB1,LB2)进行初增菌,应用选择性分离培养基PALCAM和在TSA-YE平板上进行分离,利用单增李斯特显色平板进行鉴定;根据李斯特菌的特异性基因iap基因设计引物,采用PCR方法检测所有分离的李斯特菌株;根据单增李斯特菌的特异性基因hly基因和prfA基因设计引物检测单核细胞增生李斯特菌株。结果 135份样品中共检出李斯特菌17株,检出率为12.6%;其中单核细胞增生李斯特菌4株,检出率为3.0%。结论本研究建立的PCR方法具有特异性,本市市售食品不同程度受到李斯特菌的污染。
Objective To establish a polymerase chain reaction (PCR) method for the detection of Listeria monocytogenes to understand the contamination of Listeria monocytogenes in commercial foodstuffs. Methods A total of 135 samples of raw meat, raw poultry meat, cooked meat products, aquatic products, raw vegetables and other cooked food samples were collected from Chengdu. The initial enrichment bacteria were collected by using LB1 and LB2 broths. The medium PALMAM was isolated and separated on TSA-YE plate and identified by monosodium lanthanide chromogenic plate. Based on the iap gene of Listeria monocytogenes, primers were designed and all isolates of Listeria were tested by PCR The Listeria monocytogenes strain was designed according to the primers hly and prfA of the gene specific for Listeria monocytogenes. Results 17 strains of Listeria were detected in 135 samples, with a detection rate of 12.6%. Among them, 4 strains of Listeria monocytogenes were detected, the detection rate was 3.0%. Conclusion The PCR method established in this study is specific. The Listeria monocytogenes are contaminated by the commercially available foods in our city to varying degrees.