Abstract:Diarrheagenic Escherichia coli is a common pathogen causing diarrhea in humans.This research aimed to identification of diarrheagenic Escherichia coli based on traditional microbial methods and molecular identification.Firstly，molecular identification criteria for five different types of diarrheagenic Escherichia coli were established based on polymerase chain reaction （PCR）and sequencing，and then the safety of the experimental process was evaluated，finally the applicability of this method was verified by detecting the enteroaggregative Escherichia coli in fresh meat.The results of electrophoresis showed that there were distinct bands of characteristic genes in all the five standard strains of Escherichia coli，and the bands were the same size as the products of the characteristic genes.At the same time，the consistency of glue recovery sequencing and characteristic gene sequence was 100%，so five diarrheagenic Escherichia coli could be identified by PCR and sequencing；in the safety evaluation experiment，bacterial lysate was used to coat the petri dish，and no colony formation was found after culture，so there was no biosafety risk.The results of meat samples showed that there was a target band of astA gene，and the sequencing results were consistent with this gene sequence，so this method could accurately identify the enteroaggregative Escherichia coli in fresh meat.This experiment successfully established molecular identification methods for 5 different types of Escherichia coli，evaluated the safety of the experimental process，and accurately identified the enteroaggregative Escherichia coli in meat sam－ples，it provided the theoretical basis and useful reference for the establishment and revision of laboratory related standards.