Title: Explaining the FSIS Sampling Program for Escherichia coli O157:H7 in Raw Ground Beef Kristina Barlow
1Explaining the FSIS Sampling Program for
Escherichia coli O157H7 in Raw Ground
BeefKristina Barlow, Priya Kadam, Stephanie
Buchanan, Priscilla LevineU.S. Department of
Agriculture Food Safety and Inspection Service
Office of Public Health Science
Fig. 1
Fig. 3
- Introduction
- E. coli O157H7 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 O157H7 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 O157H7 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 O157H7
outbreaks. - USDA/FSIS microbiological regulatory testing for
O157H7 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 O157H7
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
O157H7 sampling program to help protect public
health.
FSIS E. coli O157H7 Time Line
Fig. 4
Fig. 2
More sensitive laboratory method adopted
- 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 FSISs
Microbiological Laboratory Guidebook (MLG),
available online at - http//www.fsis.usda.gov/Science/Microbiological_L
ab_Guidebook/index.asp - Testing results are posted on the FSIS website
at - http//www.fsis.usda.gov/Science/Ground_Beef_E.Col
i_Testing_Results/index.asp
- How Does FSIS Use the Data?
- If ground beef tests positive for E. coli
O157H7, 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.
- Program Results
- Examining the number of recalls held in response
to E. coli O157H7 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.
For more in-depth analysis of results see Naugle
et. al. FSIS Regulatory Testing Program for E.
coli O157H7 in Raw Ground Beef. Journal of
Food Protection, Vol. 68, No. 3, 2005, Pages
462-468.