Abstract: A method for monitoring foodborne pathogenic bacteria by multiplex polymerase chain reaction （PCR）-capillary electrophoresis (CE) with a laser induced fluorescence detector was developed. Three sets of primers were designed to amplify the gene segments of uidA gene in E.coli.O157:H7, invA gene in salmonella and ipaH gene in Shigella, individually. The multiple PCR system and the separation conditions of CE were optimized. Using a capillary coated with linear polyacrylamide and sieving buffer of 7.0 g/L methyl cellulose (MC) under 8.3 kV of electric voltage, the proposed method was able to simultaneously detect the PCR products of specific genes existing in the three kinds of pathogenic bacteria within 22 min. The relative standard deviations of migration time for the detected DNA fragments were ranging from 1.47% to 2.07%. In comparison with agarose gel electrophoresis, the proposed method is rapid, sensitive and accurate.

Key words: capillary electrophoresis (CE), laser-induced fluorescence detection； foodborne pathogenic bacteria , multiplex polymerase chain reaction (multiplex PCR)