Flow cytometric detection of pathogenic E. coli in food.
E. coli O157:H7 is one of the more important food pathogens, andrapid, quantitative methods to evaluate foods for the presence of this pathogen are needed. This unit provides exactly that: a very much simplified flow cytometric assay for detection of E. coli O157:H7 in a well established vehicle of infection, ground beef. The method uses commercially available FITC-conjugated specific antibody to this bacterial serotype. Sample preparation and bacterial enrichment procedures are described. Direct and indirect approaches for quantification of the number of bacteria are given. A key feature of the assay is the reduction in time compared with plate-counting methods; the tradeoff is a slight reduction in sensitivity. Particularly useful is the simultaneous inclusion of a spiked sample to ensure a positive control. In addition, the unit provides hints on sorting the organisms if desired.
Raybourne
R B
RB
US Food and Drug Administration, Center for Food Safety and Applied Nutrition Laurel, Maryland, USA.
D000818:Animals; D000906:Antibodies; D002138:Calibration; D002417:Cattle; D002469:Cell Separation / Q000379:methods; D019453:Escherichia coli O157 / Q000378:metabolism*; D005434:Flow Cytometry / Q000379:methods; D005456:Fluorescent Dyes / Q000737:chemistry; D005506:Food Contamination; D005516:Food Microbiology; D008460:Meat / Q000382:microbiology*; D015203:Reproducibility of Results
D000906:Antibodies; D005456:Fluorescent Dyes