Acid Relief For O157:H7
Simple Change In Cattle Diets Could Cut "E. Coli" Infection,
USDA And Cornell
Scientists Report
ITHACA, N.Y. -- A simple change in cattle diets in the days before slaughter may reduce the risk of "Escherichia coli" ("E. coli") infections in humans, U.S. Department of Agriculture (USDA) and Cornell University microbiologists have discovered.
Research reported in the Sept. 11 issue of the journal "Science" indicates that grain-based cattle diets promote the growth of "E. coli" that can survive the acidity of the human stomach and cause intestinal illness. "E. coli" contamination is responsible for more than 20,000 infections and 200 deaths each year in the United States.
Fortunately there is a workable solution to the food-safety problem, the scientists say. By feeding hay to cattle for about five days before slaughter, the number of acid-resistant "E. coli" can be dramatically reduced.
"Most bacteria are killed by the acid of stomach juice, but "E. coli "from grain-fed cattle are resistant to strong acids," explains James B. Russell, a USDA microbiologist and faculty member of the Cornell Section of Microbiology. "When people eat foods contaminated with acid-resistant "E. coli" -- including pathogenic strains like O157:H7 -- the chance of getting sick increases."
"E. coli "is a normal bacterium in the gastrointestinal tract of animals and humans, and most types are not harmful (See ""E. coli" and Cattle" fact sheet, attached). However, disease-causing strains such as "E. coli" O157:H7 produce toxins that cause bloody diarrhea or even kidney failure in humans. Mature cattle are unaffected by "E. coli" O157:H7. Only a small number of cattle (estimated at 1 to 2 percent at any one time) shed "E. coli" O157:H7 in their feces, a rate that is not fully explained.
When beef carcasses are accidentally contaminated by feces at sla
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Contact: Roger Segelken
hrs2@cornell.edu
(607) 255-9736
Cornell University News Service
10-Sep-1998