Detection of Listeria monocytogenes in fish samples by PCR assay

Abstract

A total of 60 samples (25 each of fish samples and fish surface swabs and 10 dried salt fish samples) collected from various markets of Hyderabad were subjected to cult ural and PCR methods for the presence of Listeria monocytogenes. Primers derived from hlyA and iap gwere used for the detection of Listeriolysin O and p60 respectively. Four samples (2 fish samples, 2 fish surface swabs) were positive by PCR assay, whereas only two samples (one each of fish samples and fish surface swabs) were positive by cultural methods for presen ce of Listeria monocytogenes. The PCR assay detected hlyA gene of L.monocytogenes in only one fish sample. The presen ce of this organism in seafood is a great public health c oncern. The results of this study suggest that PCR could be an excellent tool for detection of Listeria monocytoge nes in sea foods as well as in livestock foods.