Occurrence of Listeria monocytogenes in raw market meat of Anand district of Gujarat, India

Listeriosis is one of the important food-borne bacterial zoonotic diseases caused by Listeria monocytogenes. The present study was undertaken to determine the presence of L. monocytogenes in raw meat of market. We collected five hundred samples, comprising 150 samples each of buffalo meat, mutton and chevon and 50 swabs from butchers’ hand, knife and log. The samples were screened using three selective plating media viz. Dominguez–Rodriguez isolation agar (DRIA), PALCAM, Oxford agar and confirmed by Christie, Atkins and Munch Petersen (CAMP) test and sugar fermentation pattern. Out of 500 samples, 13 (2.6%) samples revealed presence of L. monocytogenes, out of which 12 (2.7%) were from meat and 1 (2.0%) from swab. The highest prevalence was observed in mutton 6 (4.0%) followed by buffalo meat 4 (2.7%), chevon 2 (1.3%) and least in butcher's hand swab 1 (2.0%). The genotypic characterization of all 13 isolates was done by PCR amplification of virulence associated genes inlA (lmo0433), inlB (lmo0434), plcB (lmo0205) and inlJ (lmo2821). PCR amplification revealed that internalin genes inlA (lmo0433) and inlB(lmo0434) present in all the isolates while phospholipase gene plcB (lmo0205) in 11 (84.62%) and internalin gene inlJ (lmo2821) was present in 10 (76.92%) isolates.