# Presentation: 788613

## 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

**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**

**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**

**FSIS *****E. coli *****O157:H7 Time Line**

**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