Rapid and Sensitive Real-time PCR Quantitative Detection of Listeria monocytogenes without Enrichments in Artificially Contaminated Chilled Pork

摘要

The aim of this study was to develop a rapid real-time PCR method for detection of Listeria monocytogenes in artificially contaminated chilled pork, without the pre-enrichment steps. For specificity test, no amplification signals and no Tm at ～78.37°C were retrieved from other spoilage and pathogenic bacteria strains. The standard curve was constructed by ten-fold serial dilutions of a suspension of pure L. monocytogenes, the R2 and E were respectively 0.999 and 102.4%. The detection limits of L. monocytogenes were up to 10° cfu/ml for both pure culture and artificially contaminated chilled pork. This assay was then applied to enumerate L. monocytogenes in artificially contaminated chilled pork samples and the results were compared to those obtained by plating onto selective medium for L. monocytogenes. A comparison between two methods reported no log underestimation of the microbial loads. The real-time PCR is a useful tool for the screening of L. monocytogenes in chilled pork and was performed within 12 h, and also can accurately quantify L. monocytogenes in chilled pork samples.