Identification Of Listeria Monocytogenes In Foods By IMS-PCR

Listeria monocytogenes is a common bacterium in nature, which can occurs both inhumans and in animals. Listeriosis is a severe disease associated with a high case fatality rate.So if foods contain Listeria monocytogenes, it is very important to adopt scientific methods todetect them. IMS-PCR method can quickly detect Listeria monocytogenes in foods.IMS utilize the principle of antigen-antibody response and do Listeria monocytogenes,experiments of specificity and sensitivity. PCR is that one set of primers was designedaccording to the sequences of the iap gene（P60protein coding）of Literia monocytogenes andconducted PCR; and do Listeria monocytogenes,experiments of specificity and sensitivity.According to analyze and compare the two methods, we set up IMS-PCR and employ theformer primer to do Listeria monocytogenes,experiments of specificity and sensitivity. AlsoGuobiao(standard method of inspection) and RealTime PCR(kit) take as the control ofIMS-PCR, then analyze and compare IMS-PCR’s results.IMS can quickly entrap bacteria to increase them in culture fluid (37℃14～18h), andhemolytic reaction and rhamnose reaction can confirm if it is Literia monocytogenes, anddemands3～7days; sensitivity can attain10-7. PCR: Obtaining Literia monocytogenes fromfoods to carry out enrichment culture which need3～5days. Extract bacterial genome DNAto carry out PCR and deserve230bp, which arrive at results for4hours, its sensitivity canattain10-5. IMS-PCR: From fast collecting bacteria to progress enrichment culture, thendeserve230bp after PCR, it can detect Lisiteria monocytogenes in a day. It lessened the timeof inspection, at the same time it raised detective specificity and sensitivity of Lisiteriamonocytogenes.The results of IMS-PCR agree with Guobiao and Real Time PCR(kit), then it is moreconvenient, faster and sensitive than Guobiao; and lower cost than Real Time PCR(kit). Sofrom economy and practicability, IMS-PCR has a good prospect to use and value to study.