Incidence of Listeria species in bulk tank milk and meat from sheep’s in Kerman, Iran

Introduction and objective: Listeria Spp, especially Listeria.monocytogenes are opportunistic pathogens affecting all individuals, although immunocompromised, elderly and pregnant women are especially at risk. These bacteria are among important food born infections around the world. This study was performed to determine the prevalence of Listeria Spp from milk and meat samples of sheep in Kerman. Materials and Methods: Totally 300 sample of milk from sheep flocks (n=150) and meat (150 sample) from butcher shops were collected. The Listeria Spp were identified by standard biochemical tests and MicrogenTM Listeria-ID System. All the culture positive isolates were confirmed by PCR methods using primers for identification of hly, prf and iap genes. Results: A total of 18 isolates were identified as Listeria Spp, comprising 13 isolates from meat and 5 isolate from milk. The most frequent species were L.ivanovii (n=9), followed by L.gravi (n=7) and L.welshimeri (n=2). L.monocytogenes was not isolated in this study. Conclusion: the prevalence of Listeria Spp in sheep samples in this study was low, with no incidence of the common pathogen of the group, L.monocytogenes. Since the foods can be contaminated during processing and the importance of this food born pathogen, study on other type of food products from animal origins such as cows and vegetables is necessary in order to control this opportunistic pathogen in the food chain.