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Regulation of Shiga Toxin Production in E. coli from Bovine and Human Sources

LeJeune, Jeffrey
Ohio State University
Start date
End date

Highly publicized outbreaks of food-borne illness since 1993, primarily caused by bacteria such as E. coli O157:H7, Salmonella spp. and Listeria monocytogenes, elicited intense consumer concern about meat safety. In response, regulatory authorities, researchers and the beef industry initiated efforts to implement food safety management systems that would improve microbiological quality. The USDA Food Safety and Inspection Service (FSIS) began initiating new regulatory requirements during the mid-1990s. Packers were required to knife-trim carcasses to remove all visible contaminants, comply with written sanitation standard operating procedures (SSOP), implement Hazard Analysis Critical Control Point (HACCP) systems, and meet microbiological performance criteria and standards for E. coli and Salmonella as a means to verify HACCP effectiveness and pathogen reduction.

Researchers and beef packers/processors have addressed consumer food safety concerns by developing a variety of methods that are now implemented, or are being further developed, to reduce numbers of bacteria on beef and beef products and improve microbiological safety. These microbiological decontamination technologies include:
  • Animal cleaning;
  • Chemical dehairing at slaughter;
  • Spot-cleaning of carcasses by knife-trimming or steam/hot water vacuuming; and
  • Spraying/washing/rinsing of carcasses before evisceration and/or before chilling, with water, chemical solutions and/or steam or hot water.

Certain strains of the Shiga toxin-producing bacterium E. coli have emerged as an important cause of food-borne disease around the world. The most common Shiga-toxin producing E. coli strain in the United States is known as E. coli O157. The main objective of this study was to develop a simple and rapid molecular test that can distinguish between strains of E. coli O157 that produce large amounts of toxin from those that produce very little toxin.

Funding Source
Nat'l. Cattlemen's Beef Assoc.
Project source
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Bacterial Pathogens
Natural Toxins
Escherichia coli