Assessing Current Practices and Testing for E. coli O157:H7 in Beef Production: The Case of Beef Trim and Ground Beef

By Wendy J. Dixon, Noralhuda Ismail and George Kaladjian.

Published by Food Studies: An Interdisciplinary Journal

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E. coli O157:H7 is a food-borne pathogen, causing in some cases severe illness and even death, which is transmitted mostly through consumption of beef products. In the past ten years, disease outbreaks or detection of Escherichia coli (E. coli) O157:H7 in the food supply chain have led to recalls of beef products, including one recall for 21 million pounds of beef. Because of the consequences of E. coli O157:H7 contamination in beef products, we examined the impact of the contamination, the outbreaks, the recalls, the annual Food Safety and Inspection Service’s (FSIS) E. coli O157:H7 results, the current sampling procedure, and the FSIS guidelines. Since 2001, monitoring of beef trim and ground beef by FSIS has shown an overall decline in percent of beef samples testing positive for E. coli O157:H7, primarily due to improvement in the hygienic production of ground beef. However, over the same duration, the guidelines set by FSIS for the level of E. coli O157:H7 contamination in ground beef has been met in only 5 out of 13 years, which points to a need for continued improvement in the production of ground beef. Although testing methods have improved over the period, some contaminated beef goes undetected. Outbreaks, recalls, and Shiga-toxin producing E. coli (STEC) infections in humans still occur. We know some contaminated beef goes undetected because of inherent limitations in current sampling methods. For example, at the current 0.5% to 1.0% level of contamination of beef trim by E. coli O157:H7, the current sampling practice of sixty pieces (N60) is not adequate to detect all contaminated lots of beef at the 95% confidence level. Reducing production volume, keeping batches separated, and adjusting sample size to production volume have probably contributed to the decrease in levels of E. coli O157:H7 in ground beef. Continuing and enforcing these practices should keep contamination levels below the 0.2% that the guidelines recommend. Additional changes are probably needed to achieve levels below the 0.2% amount, which is necessary to achieve future public health goals. In recent years, the food-borne infections due to non-O157 STECs have been steadily increasing and are now at levels comparable to infections due to E. coli O157:H7. The non-O157-STECs can be spread through beef and therefore, the non-O157 STECs should be monitored in ground beef. FSIS has begun to establish procedures and guidelines for monitoring the presence of non-O157 STECs in beef products. This is a step in the right direction. Similar approaches to those used for E. coli O157:H7 should help decrease infections caused by non-O157 STECs.

Keywords: Beef, Ground Beef, Beef Production, E. coli O157:H7, STEC, non-O157 STEC, Food-borne Disease, Outbreak, Recall, Sampling Method, FSIS Guideline, Food Safety, Diarrheagenic E. coli, Food Contamination

Food Studies: An Interdisciplinary Journal, Volume 2, Issue 2, pp.57-71. Article: Print (Spiral Bound). Article: Electronic (PDF File; 468.358KB).

Dr. Wendy J. Dixon

Associate Professor, Biological Sciences Department, California State Polytechnic University, Pomona, CA, USA

Wendy J. Dixon is an associate professor in the Department of Biological Sciences at California State Polytechnic University at Pomona. Prior to this position, she worked as a Senior Staff Fellow at the U. S. Food and Drug Administration. She has background in molecular biology, cell biology, microbiology and regulatory affairs. Her research interests include science policy and regulations, testing of antibody-based lateral wicking methods for detection of bacteria, use for detection of coliforms in water samples, determination of sensitivity and specificity for such methods, cell cycle regulation in Saccharomyces cerevisiae, the G1/S phase transition, Cdc7/Dbf4 kinase, and response of S. cerevisiae to genotoxic stress.

Noralhuda Ismail

California State Polytechnic University, Pomona, CA, USA

Noralhuda Ismail was an undergraduate student in the Department of Biological Sciences at California State Polytechnic University at Pomona. She completed the Bachelor of Science degree and went on to work in the meat industry.

George Kaladjian

Student, Biological Sciences Department, California State Polytechnic University, Pomona, CA, USA

George Kaladjian was an undergraduate student in the Department of Biological Sciences at California State Polytechnic University at Pomona. He completed the Bachelor of Science degree and is currently applying to graduate schools.