Validación de PCR para detección de Listeria monocytogenes en carnes de res y pollo

Listeria monocytogenes is a zoonotic emergent microorganism in the food industry, being from great interest for the public health. The aim of this work was to validate the PCR technique for the detection of Listeria monocytogenes in raw meats of beef and chicken. The DNA extraction procedure was carried out with lisozyme, proteinase K and phenol-cloroform, starting from artificially contaminates samples. The specificity of primers LI1 and U1 was verified by the amplification of a 938bp band corresponding to a fragment of rDNA 16S; in the same way the «primers» LF and LR amplified a band of 750bp corresponding to the hlyA gene; allowing the genus (938bp band) and species (750bp band) identification respectively. Other bacterial strains assayed did not amplify any of the Listeria specific bands. The detection limit for PCR was of 10 2 and 10 4 UFC/gr on beef and chicken meat respectively; the Gold Standard reported 10 2 UFC/ml in both cases. The comparison of the PCR versus the Gold