Evaluation of various selective and non selective broths for detection of Listeria monocytogenes in pork and for PCR compatibility

The present study was undertaken to standardize PCR assay for detection of hly A (Listeriolysin O) and iap(p60) of L.monocytogenes from livestock foods and compare its efficacy with conventional cultural methods. A set of primer derived from iap gene and other set derived from hlyA gene were used for detection of L. monocytogenes and Listeriolysin O in the PCR assay. Electrophoresis analysis revealed the specific amplification products at 131 bp and 456 bp respectively for iap and hlyA genes. Three different template preparation methods viz. genomic DNA extraction, heat lysis and lysis buffer methods were compared to determine the most sensitive, rapid and simple method suitable for PCR technique. The two non-selective broths (Brain Heart Infusion broth and Tryptone Soya Broth) and two selective broths (LEB and PALCAM) were also evaluated for PCR compatibility.