MOLECULAR SCREENING OF LISTERIA MONOCYTOGENES FROM COMMERCIAL FOOD STUFFSARUNAVA DAS*, A. KARTHIKEYAN AND A. MUGHUN DEV
Listeria monocytogenes recognized as the major food borne pathogen that causes listeriosis in animals and human beings. Present study was undertaken to determine the prevalence of pathogenic strains of L. monocytogenes from commercial food stuffs. A total of 389 food samples comprising meat, fish products, milk, dairy products, raw vegetables, bakery, beverage and fermented rice products, collected from various randomly selected local retail shops, local markets and supermarkets of Tamil Nadu were investigated for the presence of L. monocytogenes. Identification of pure bacterial isolates up to the genus and species level was done by performing arrays of biochemical tests and polymerase chain reaction assay respectively. Bacterial identification revealed 82 (21.07%) suspected isolates of L. monocytogenes. All the isolates were screened for the presence of virulence associated genes like haemolysis (hlyA) and invasive associated protein (iap) of L. monocytogenes by duplex PCR. In duplex PCR, iap gene (131bp) and hlyA gene (456bp) were detected in 82 (100%) and 58 (70.73%) isolates respectively. Present result suggested that PCR is a rapid and sensitive method of identification of L. monocytogenes from commercial human consuming food samples.
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