E. coli

Image by Trevor M from Pixabay

Generic E. coli is a normal flora resident of the bovine gastrointestinal tract. It poses little danger as a foodborne disease. However, the O157 serotype of E. coli can be extremely dangerous to young, old, and immunocompromised individuals.

E. coli O157 is a transient resident of cattle. It can be found on most cattle farms at various times. It may arrive on a farm with a truckload of feed, or it can be carried by a newly purchased animal. The bacteria rarely causes disease in cattle and can live for long periods of time in water trough sediment and manure. Peaks in E. coli O157 prevalence occur during summer and late fall, possibly because the bacteria can reproduce rapidly in warm weather.

Ingesting as few as 10 organisms can cause clinical disease in humans, including bloody diarrhea, severe abdominal cramps, nausea, vomiting, and renal failure.

The association of feed and water with salmonella and E. coli O157 prevalence in cattle: A current study funded by an FDA grant focuses on feed and water as sources of E. coli O157 and salmonella infection.

Chlorination as a tool in fighting E. coli O157 and campylobacter

Starting in May of 2000, we will be researching the effect of chlorinated water on the prevalence of E. coli O157 and Campylobacter jejuni in feedlot cattle. This new study will be funded by a USDA grant.

Current research goals

  • Determining the “normal” level of generic E. coli present in water, total mixed rations and bunk feeds on dairies.
  • Determining prevalence of E. coli O157 in purchased cattle feeds.
  • Determining prevalence of E. coli O157 in cattle.
  • Determining prevalence of E. coli O157 in water troughs.
  • Determining survival characteristics of E. coli O157 in experimental mixed rations and total mixed rations from dairies.
  • DNA fingerprinting E. coli O157 isolates from farms and possible reservoirs and sources.
  • Determining the effects of chlorinated water on both prevalence of E. coli O157 and weight change in feedlot cattle.


  • Hancock, D., T. Besser, D. Rice, C. Gay, J. Gay. Pre-harvest food safety interventions on cattle farms.
  • Jay, J.M. Modern Food Microbiology, Fifth Edition. New York: Chapman and Hall, 1996.