more details in Agricultural Research.
Reducing Salmonella and E.
coli 0157:H7 at the Farm By
March 5, 2001
A practical approach to reducing two key on-farm pathogens in
pigs and cows has been developed by Agricultural Research Service researchers
in College Station, Texas. The scientists report that sodium chlorate, fed in
low doses to pigs and cows before slaughter, selectively kills the pathogens
Salmonella typhimurium and E. coli 0157:H7.
The scientists in the ARS Food
and Feed Safety Research Unit in College Station developed an animal model
showing that sodium chlorate reduces these harmful bacteria in the animal
intestinal tract. Gut and lymph tissue in meat animals and chickens are major
reservoirs for salmonella and E. coli 0157:H7. The U.S.
Centers for Disease Control and Prevention
estimate that about 1.4 million cases of salmonellosis and 73,000 cases of
diarrheal illness caused by 0157:H7 occur in the U.S. each year.
Salmonella and E. coli 0157:H7 have an
enzyme--respiratory nitrate reductase--that beneficial intestinal bacteria
lack. This enzyme converts the sodium chlorate to chlorite, which kills the
harmful bacteria. Because the beneficial bacteria lack respiratory nitrate
reductase, they are unharmed by the added chlorate.
In laboratory studies, 45 weaned pigs were fed as much as 0.04
grams of sodium chlorate per kilogram of body weight after being inoculated
with S. typhimurium. Within 16 hours, the treatment produced a 150-fold
reduction in the number of pathogenic cells in the intestines.
The U.S. Department of
Agriculture applied for a patent on behalf of the inventors, ARS
microbiologists Robin C. Anderson and David J. Nisbet in College Station and
Larry H. Stanker in Albany, Calif. The researchers are seeking a cooperative
research partner to further develop the work for commercial meat processing.
Besides adding the chlorate to feed, the researchers suggest that a more
realistic approach would be to add the chlorate to drinking water for the
animals upon arrival at the processing facility. However, the
Food and Drug Administration would need to
approve any wide-scale use of the technique in food processing facilities.
For more details, see the March issue of Agricultural Research.
ARS is the chief scientific research agency of USDA.
Scientific contacts: David J. Nisbet, ARS Food & Feed
Safety Research, College Station, Texas, phone (979) 260-9368, fax (979)
260-9332, email@example.com or
Robin C. Anderson (979) 260- 9317, firstname.lastname@example.org.