Rapid detection of Listeria monocytogenes in food by multiple PCR.

【Objective】 A multiple polymerase chain reaction(PCR) system was developed to detect Listeria monocytogenes(LM),the more important food born pathogens,and applied to detect LM from food samples.【Method】 Template DNA was obtained by thermolysis broth cultured bacteria and thermolysis colony.Primers were designed according to the 16S rRNA,inlAB,iap,hly genes.The concentration of primers and annealing temperature were examined and optimized.【Result】 The PCR products were not detected in other Listeria spp,including L.innocua,L.seeligeri,L.welshimeri,L.ivanovii,L.grayi and in Vibrio parahemolyticus,indicating that this method was highly specific for L.monocytogenes.The detection limit of the PCR assay was 102 CFU/mL of pure cell culture.The PCR assay could detect no more than 0.4 CFU/g of L.monocytogenes in the contaminated pork.【Conclusion】 The results show that the colony PCR method is better,the method assay is highly sensitive,specific,rapid and accurate and can be used for rapid detection of L.monocytogenes in food.