UNIT 11.6 Flow Cytometric Detection of Pathogenic E. coli in Food

  1. Richard B. Raybourne

Published Online: 1 MAY 2001

DOI: 10.1002/0471142956.cy1106s08

Current Protocols in Cytometry

Current Protocols in Cytometry

How to Cite

Raybourne, R. B. 2001. Flow Cytometric Detection of Pathogenic E. coli in Food. Current Protocols in Cytometry. 8:11.6:11.6.1–11.6.9.

Author Information

  1. U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition Laurel, Maryland

Publication History

  1. Published Online: 1 MAY 2001
  2. Published Print: APR 1999


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.