Detection of Viable Listeria monocytogenes in Dairy Products By Real Time Reverse-Transcription PCR

Listeria monocytogenes is a food-borne pathogen which can cause zoonosis. A detection method based on real time reverse-transcription PCR amplification of mRNA was established in the study. This method can overcome false-positive result caused by amplification of nonviable L.monocytogenes. Sensitivity and specificity of the method were studied, as well as artificially contaminated dairy products by L.monocytogenes, dairy products from market and L.monocytogenes biofilm. For contaminated milk, detection sensitivity was 17CFU/ml after 6 h enrichment. Detection limit in biofilm was 2times10²CFU/cm² after 7 h enrichment. The results indicate that the method can satisfy detection of L.monocytogenes in dairy products and biofilm.