Rapid Detection Of Food-borne Listeria Monocytogenes By Loop-mediated Isothermal Amplification

Listeria monocytogenes is a widespread pathogenic bacteria and widely distributed innature that can infect animals and human beings. Listeria monocytogenes has become one ofthe most serious problems which have bad effect on public health in our country. The foodpoisoning caused by Listeria monocytogenes is going up in recent years. It is a veterinary,food safety and public health aspects of important issues to strengthen the assessment andcontrol of Listeria monocytogenes in food. Traditional method for routine detection ofListeria monocytogenes is complex and time-consuming. It takes from4to7days. Themethod cannot fulfill the need for detecting food-borne pathogens rapidly.In2000, Notomi T. and his colleagues developed a novel nucleic acid amplificationtechnology which was noted as Loop-mediated Isothermal Amplification (LAMP). LAMPassay is a specific, sensitive and rapid method of detecting viruses, bacteria and geneticallymodified food.In this study, we developed a rapid and sensitive hlyA-based LAMP assay on a real-timeturbidimeter platform for the detection of Listeria monocytogenes in food. There was no falsepositive or false negative result in the experiments on specificity of the LAMP assay. Whentesting10-fold serial dilutions of Listeria monocytogenes ATCC19115DNAand pure culture,the detection limit was92fg per reaction and13CFU per reaction respectively, up to10-foldmore sensitive than that of PCR. The LAMP assay was able to detect Listeria monocytogeneseven though the sample was contaminated with very low concentration after3h enrichmentculture. Furthermore, compare to the Chinese National standard GB4789.30－2010, theLAMP assay was96.67%match ratio and the assay combined with enrichment was100%match ratio when applied in food samples.Results from this study showed that the hlyA-based LAMP assay is an effective method forthe rapid detection of Listeria monocytogenes in food.