Escherichia coli O157:H7 contamination of raw beef products: high event periods present a challenge to the current model

Authors: Arthur, Terrance

Submitted to: American Meat Science Association Conference Reciprocal Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/28/2014
Publication Date: 6/20/2014
Citation: Arthur, T.M. 2014. Escherichia coli O157:H7 contamination of raw beef products: high event periods present a challenge to the current model. In: Proceedings of the American Meat Science Association. Reciprocal Meat Conference, 6/15-6/18/2014, Madison Wisconsin. http://www.meatscience.org/

Interpretive Summary:

Technical Abstract: Escherichia coli O157:H7 is a foodborne pathogenic bacterium that resides in the intestinal tract of cattle and has been associated with a variety of foodstuffs including raw beef products. While most E. coli are harmless to humans, a handful of E. coli types can cause disease. E. coli O157:H7 is possibly the most virulent of all pathogenic E. coli capable of causing severe disease and even death. It was through a major disease outbreak that E. coli O157:H7 came to the forefront of food safety concerns in the beef industry. Shortly after this outbreak, the Food Safety Inspection Service (FSIS) declared raw non-intact beef products containing E. coli O157:H7 to be adulterated, requiring any such products to be excluded from commerce. This marked the first instance where bacterial contamination of a fresh meat product was considered adulteration in the U.S. In the present state of the beef industry, most beef processing companies test all of their raw beef trim before release into the food supply, a procedure referred to “test-and-hold”. By testing all lots of raw beef trim at the time of production, the beef industry has been able to collect a great deal of data pertaining to finished product contamination. Through such data analysis, it was seen that individual processing plants occasionally experience peaks in contamination rates, termed high event periods (HEP), where multiple E. coli O157:H7-positive lots are clustered in a short time frame. Through a study by Arthur et al. it was determined that individual HEP show little to no diversity of strain genotype. Hence, each HEP has one strain type that makes up most if not all of the contamination. This is shown to differ from the genotypic diversity of E. coli O157:H7 found on the hides of cattle entering processing plants and presents a challenge to the existing model for raw beef trim contamination.