Identification of Listeria monocytogenes contamination sources in two fresh sauce production plants by pulsed-field gel electrophoresis Original Research Article

Twenty-three Listeria monocytogenes strains isolated from two food-processing plants, which produce fresh sauces, were serologically characterized and tested by the mouse biological assay and molecular typing by pulsed-field gel electrophoresis (PFGE). The use of PFGE for the characterization of these L. monocytogenes strains provided, in plant A, valuable information about potential sites of cross-contamination and in plant B, a valuable insight into the presence of endemic strains. The use of highly discriminating typing techniques such as PFGE and the thorough observance of GMPs and the HACCP system can reduce the incidence of L. monocytogenes in food-processing plants.