1. Explaining the FSIS Sampling Program for Escherichia coli O157:H7 in Raw Ground Beef Kristina Barlow, Priya Kadam, Stephanie Buchanan, Priscilla Levine U.S. Department of Agriculture Food Safety and Inspection Service Office of Public Health Science Abstract The Food Safety and Inspection Service (FSIS) routinely samples raw-ground beef (RGB) for Escherichia coli O157:H7. This presentation describes sample- collection procedures, summarizes results, and explains how FSIS utilizes the data to help protect public health. Samples are collected from RGB products for regulatory testing, and from beef patty components and RGB components for baseline testing, from federal, retail, state, and import establishments, according to Directive 10,010.1. Federal establishments are randomly selected for sampling, with each establishment having an equal chance of being sampled. One-pound samples are aseptically collected, shipped overnight to FSIS laboratories, and analyzed using methods in the Microbiology Laboratory Guidebook. If samples test positive, and product was not held, it is recalled. After a positive, establishments reassess their Hazard Analysis and Critical Control Point (HACCP) programs, and a follow-up sample may be collected. From CY 1994-2005, a total of 279/79,910 (0.35%) samples tested positive. The number of positives increased in the summer and fall for CY 2001 and 2002, and in response, FSIS collected more samples (June-September) until rates decreased. Over time more products represented by samples were held, resulting in fewer recalls. Increases in percentage of positives before CY 2000 could have been due to changes in laboratory methodology. Decreases after CY 2000 could have been due to changes in FSIS policies and increased industry response to these policies. Results are used by FSIS to identify establishments where further corrective actions are needed, and to help protect public health by keeping adulterated product from reaching the marketplace. Introduction E. coli O157:H7 was first recognized as a foodborne pathogen with major public health consequences in 1982, when it was associated with 2 outbreaks of bloody diarrhea in Oregon and Michigan. Infection with E. coli O157:H7 can lead to hemolytic uremic syndrome (HUS) and hemorrhagic colitis and even death. There are an estimated 73,500 cases and 60 deaths per year from E. coli O157:H7 in the USA. According to surveillance results from Centers for Disease Control and Prevention (CDC) from 1982 through 2002, ground beef was the food vehicle for 41% foodborne E. coli O157:H7 outbreaks. USDA/FSIS microbiological regulatory testing for O157:H7 is performed for raw ground beef (RGB), and beef patty components and RGB components are tested for baseline studies. Samples are collected from federal plants, retail stores, state plants, and import establishments. Purpose of this Poster FSIS routinely posts results from E. coli O157:H7 testing program in tabular format on its website. However, little background, interpretation, and discussion is provided. The purpose of this poster is to: describe the context of the sampling program, provide a more in-depth analysis of the data, and explain how FSIS utilizes data from the E. coli O157:H7 sampling program to help protect public health. Sample Collection and Testing Establishments are selected randomly for sampling. Raw ground beef was collected (1/2 pound before 1997 and 1 pound after 1997) and shipped overnight to the FSIS Field Service Laboratories (FSL). Samples are analyzed using methods in FSIS’s Microbiological Laboratory Guidebook (MLG), available online at: http://www.fsis.usda.gov/Science/Microbiological_Lab_Guidebook/index.asp Testing results are posted on the FSIS website at: http://www.fsis.usda.gov/Science/Ground_Beef_E.Coli_Testing_Results/index.asp Program Results Examining the number of recalls held in response to E. coli O157:H7 positives from CY 2001-2004 shows that as the program progressed, more samples were held, resulting in fewer recalls (Fig. 1). From CY 1994 through 2005, about 63.7% of the positive samples came from federal plants, 35.1% from retail stores, 0.5% from state plants, and 0.7% from imports. Over this time period, FSIS increased the number of samples collected from federally inspected establishments, in response to higher percentage positives in these samples (Fig. 2). Early in the sampling program (CY2001 and 2002) there were higher number of positives during the summer months. In response to this, FSIS increased sampling during these months. In later years (CY 2003-2005), numbers of positives were low during all months of the year (Fig. 3). Examining the percentage positives over time showed an increasing then decreasing trend. Increases before CY 2000 could have been due to changes in laboratory methodology. Decreases after CY 2000 could have been due to changes in FSIS policies and increased industry response to these policies (Fig. 4). Acknowledgements We would like to thank the FSIS personnel who collected the samples and the laboratory personnel who analyzed them. We would also like to thank reviewers who helped provide useful feedback for this project. Results Percent Positive Samples by Year FSIS E. coli O157:H7 Time Line Commercial PCR-based screening procedure introduced All federally inspected plants producing raw ground beef subject to testing HACCP plans reassessed due to human illness More sensitive test for detecting E. coli: immunomagnetic separation before plating on selective medium. Revised instructions for sample collection to improve detection of E. coli O157:H7—25g sample changed to five 65g (325g total) sub-samples Zero tolerance reemphasized for visible fecal contamination on carcasses to reduce microbiological hazards on raw meat products PR/HACCP regulations E. coli O157:H7 declared adulterant in RGB— microbiological testing program expanded 2005 2003 2002 1999 1998 1997 1996 1994 Fig. 1 Fig. 2 Fig. 3 Fig. 4 For more in-depth analysis of results see: Naugle et. al. “FSIS Regulatory Testing Program for E. coli O157:H7 in Raw Ground Beef.” Journal of Food Protection, Vol. 68, No. 3, 2005, Pages 462-468. How Does FSIS Use the Data? If ground beef tests positive for E. coli O157:H7, and the product was not held by the establishment, FSIS will initiate a recall. Sampling frequencies are adjusted based on program results (e.g. increased sampling during summer months). Data are used to initiate new sampling programs, such as the trim baseline (samples raw-ground beef components) and to develop future programs such as risk-based sampling (more samples collected in riskier establishments). Incident Investigation Teams (IIT) are sent to establishments with high levels of positives to help determine how levels can be decreased. Positive samples are further analyzed to obtain pulsed-field gel electrophoresis (PFGE) patterns. These patterns are compared to patterns from clinical isolates to detect outbreaks and illnesses. More sensitive laboratory method adopted