Frequency determination of listeria contamination in dairy products and their antibiotic resistance pattern, department for controlling food stuffs, Lorestan

Listeria monocytogenes has been identified as a serious food-borne pathogen. There is concern that raw dairy products maybe source of listeria strains responsible for human listeriosis. The aim of this study was determination of listeria from daily products which transferred to laboratory of food stuffs in Lorestan. In this study 720 different dairy samples sent to the food stuffs control laboratory were analyzed for the presence of listeria spp. A series of test including catalase production, CAMP test, VP and fermentation of xy lose and manitol were used for listeria identification. Finally antimicrobic resistance was determined. Listeria monocytogenes was found in 9.72% of the samples and listeria innocua and listeria seeligeri were found in 5.83% and 1.11% of the samples, respectively. There were not any other isolated of listeria In the antibiogram, all of isolates were susceptible to penicillin, ampicillin, co-trimoxazole, and gentamycin and 5 isolates were resistant to erythromycin. In view of that dairy products were ready to eat and there were possibility of contaminated by listeria spp. So, isolation and diagnosis of this in dairy products is important.