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Rapid screening of beef for the presence of Escherichia coli 0157:H7 was shown to be feasible using a 10 hour enrichment in modified buffered peptone water and the antibody-direct epifluorescent technique (Ab-DEFT). The Ab-DEFT involved membrane filtration, fluorescent antibody straining and epifluorescence microscopy and was accomplished in less than 1 hour.
The procedure allowed detection of the pathogen artificially inoculated into beef patties at 0.1 CFU/g. The 10 hour nonselective enrichment broth supported rapid growth, which provided sufficient numbers of cells for a positive determination by the Ab-DEFT after scanning no more than 10 microscope fields using a 40X objective lens. Immunomagnetic separation using anti-E. Coli 0157 Dynabeads7 was shown to be a sensitive method that can be used to confirm presumptively positive cultures within 24 hours. The ease and rapidity of the Ab-DEFT can provide a substantial time and cost savings to the beef industry for E. coli 0157:H7 testing.