Food Protection Trends - September 2010 - 529

INTRODUCTION
Healthy People 2010 is a comprehensive framework outlining disease prevention and health promotion objectives for the United States (7). The goal of the food safety focus area is to reduce foodborne illnesses, with the specific objectives of reducing infections caused by Campylobacter, E. coli O157:H7, Listeria monocytogenes, and Salmonella and reducing outbreaks caused by E. coli O157:H7 and Salmonella Enteritidis (7). According to the Centers for Disease Control and Prevention (CDC), foodborne infections contribute to approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the U.S. each year (9). In 2007, there were 1,097 outbreaks reported electronically to CDC’s Electronic Foodborne Outbreak Reporting System; 257 (23%) of those were confirmed to be attributed to a bacterial etiology and 199 (18%) to a viral etiology (1). There were 36 E. coli O157:H7 outbreaks reported to CDC in 2007 (1). The Food Safety and Inspection Service (FSIS) coordinated 21 voluntary recalls of ground beef products in 2007, 10 of which were associated with E. coli O157:H7 infections. This paper describes the inter-agency collaboration during one of the E. coli O157:H7 investigations. Foodborne illness investigations that span multiple agencies and jurisdictions have become more common as the U.S. food supply chain has become increasingly complex because of wider distribution of products produced domestically and internationally. Further, advances in epidemiologic and laboratory surveillance have enabled the identification of foodborne outbreaks. Consequently, successful investigations require efficient communication and coordination among local, state, and federal public health agencies and regulated industries. The ability to control and mitigate a foodborne outbreak to prevent further illnesses depends upon rapidly identifying contaminated food products and taking control measures to limit consumers’ exposure to contaminated products, including removal of these products from commerce whenever possible. FSIS is the public health regulatory agency within the U.S. Department of Agriculture responsible for ensuring that the nation’s commercial supply of meat, poultry, and processed egg products is

safe, wholesome, and correctly labeled and packaged. To ensure compliance with U.S. food safety standards, FSIS inspects and monitors all meat, poultry, and processed egg products sold in interstate and foreign commerce. The Foodborne Disease Investigations Branch (FDIB) is the point of contact linking public health partners (local and state health departments, local and state agricultural departments, and other federal agencies) to FSIS experts on a variety of food safety issues. FDIB is staffed by public health professionals with backgrounds in epidemiology, environmental health, veterinary medicine, clinical medicine, and other related disciplines. During foodborne illness investigations, FDIB assesses epidemiologic information, assists with traceback of implicated foods to producing establishments, facilitates sampling to identify pathogens that may be causing human illness, and provides information to FSIS senior management.

WESTERN STATES E. COLI O157:H7 INVESTIGATION
On May 25, 2007, FDIB was notified by the FSIS Liaison to CDC of a cluster of eight case-patients with an indistinguishable pulsed-field gel electrophoresis (PFGE) pattern combination, in Arizona, California, Colorado, Utah, and Wyoming. California casepatients purchased ground beef products from Grocery Store A. Colorado, Utah, and Wyoming case-patients purchased ground beef products from Grocery Chain B in their respective states. On May 30 and May 31, 2007, E. coli O157:H7 was confirmed in leftover ground beef products collected from California and Colorado case-patients, respectively. Personnel from FSIS and the California Dept. of Public Health, Food and Drug Branch (FDB) conducted a joint traceback investigation on May 31, 2007 at the California retail stores to identify production dates corresponding to the positive leftover products. Limited packaging material from the California case-patient initially identified Establishment X as the supplier of ground beef products purchased at Grocery Store A. No labeling information was available for the Colorado case-patient. A review of grinding logs and invoices corresponding to case-patients’ purchase dates iden-

tified Establishment X as the supplier of ground beef products to both California and Colorado retail locations. FSIS Office of Program Evaluation, Enforcement and Review investigators from California and Colorado and the FDB initiated a traceback investigation to determine if products from common production dates were distributed and available at retail locations. After a thorough record review, FSIS determined that ground beef products produced on April 20, 2007 by Establishment X were common to the retail locations in California and Colorado. As a result, the establishment voluntarily recalled 75,000 pounds of ground beef products on June 3, 2007. Further investigation by the FDB identified April 13, 2007 as an additional production date of interest. Through the review of invoices and distribution information at the grocery stores, FSIS confirmed the involvement of the additional production date. As a result, on June 6, 2007, the establishment expanded the initial recall to include 375,000 pounds of ground beef products produced on April 13, 2007. The Wyoming and Utah case-patients were unable to provide further details on the dates of purchase; therefore, traceback investigations at those retail stores could not be conducted. On June 1, 2007, the Arizona Dept. of Health Services (ADHS) reported six case-patients with E. coli O157:H7 infections, two with a PFGE pattern combination indistinguishable from the outbreak pattern. Case-patients reported purchasing ground beef products at Grocery Chain C. Leftover product from two case-patients was presumptive positive for E. coli O157:H7 on June 5, 2007. A traceback investigation initiated by FSIS also identified Establishment X as the ground beef supplier. Based on the findings from the FSIS investigation and the ADHS epidemiologic investigation, the establishment announced a second expansion of the recall on June 9, 2007 for 5.7 million pounds of ground beef products produced between April 6 and April 20. After the second recall expansion, ADHS continued to find case-patients with the outbreak strain and a suggestive food history. However, either those casepatients were lost to follow-up or information from supermarket grinding logs was found to be incomplete or partly inaccurate.

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Food Protection Trends - September 2010

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