Escherichia coli O157:H7 in Ground Beef Review of a Draft Risk Assessment (2002) / Chapter Skim
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1 Summary of the Food Safety and Inspection Service Draft Risk Assessment
1 Summary of the Food Safety and Inspection Service Draft Risk Assessment
Pages 13-26
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From page 13... ...
1~.~ The attendant model follows each step of the production process, from the prevalence of the pathogen in cattle on the farm to its presence in a single serving of cooked ground beef. ~ The complete text of the draft risk assessment may be found on the FSIS web site (www.fsis.usda.gov)
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From page 14... ...
This chapter summarizes the content of the FSIS risk assessment as presented in the draft report and is intended as a reference for readers who do not have ready access to that document.2 The draft risk assessment itself is reviewed in the next five chapters and the modeling approach and implementation in Chapter 7. The model is divided into three exposure assessment modules (Production, Slaughter, and Preparation)
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From page 15... ...
cold 0157:H7 prevalence is significantly higher in feedlot cattle than in breeding cattle. An evaluation of herd prevalence and within-herd prevalence in breeding and feedlot cattle did not alter that finding.
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From page 16... ...
Because breeding cattle are not specifically raised for slaughter, it is not uncommon for them to make their way to livestock markets and then slaughter plants individually rather than in an established herd from one farm. Therefore, it is assumed that the prevalence of E
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From page 17... ...
Average carcass weights have been determined for each type of cattle: breeding cattle (dairy cattle and calves) and feedlot cattle (steers
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From page 18... ...
Trim is removed from each carcass and combined into 2,000-pound combo bins during the slaughter process. Combo bins are typically large cardboard boxes lined with plastic that are used to collect meat trim.
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From page 19... ...
To estimate the lower frequency of contamination during the low-prevalence season, the same data are used, but more uncertainty is introduced into the calculation by creating a "mixture" of the transformation ratio and a uniform distribution, which ranges from near zero to a maximum of the transformation ratio found during the high season. On the basis of data from research papers and the FSIS national baseline survey of slaughter plants (1994)
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From page 20... ...
Second Decontamination The first and second decontamination steps are similar in that knives and spot steam vacuuming are used to remove visible contamination from carcasses. The model assumes that small plants use, in addition, hot-water rinsing, sometimes with organic acids.
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From page 21... ...
Breeding cattle are processed in the same way, but trim is a primary product rather than a byproduct that results from deboning. Once the trim is removed from the carcass, it moves on conveyer belts to combo bins or to vacuum-packaging areas.
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From page 22... ...
cold 0157:H7 organisms during the low and high seasons, respectively; an average of 23% and 43% of combo bins containing meat from feedlot cattle are contaminated during the low- and high-prevalence seasons. The disparity in prevalence between breeding and feedlot cattle is due primarily to variations in their living conditions, feeding practices, and processing before they enter the slaughter plant.
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From page 23... ...
To produce ground beef with a specific fat content, it is necessary to combine trim from different combo bins. Trim from breeding cattle is routinely mixed with trim from feedlot cattle.
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From page 24... ...
Consumption Three primary types of ground beef are modeled in the consumption portion of the Preparation Module: raw ground beef, hamburger patties and sandwiches, and such products as meatballs and meatloaf whose major ingredient is formed ground beef. Consumption patterns at and away from home and the age of the consumer are factored in.
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From page 25... ...
To determine how many cases of E cold 0157:H7-induced illness occur in the United States annually, information was gathered from the 19961999 Emerging Infections Program, Foodborne Disease Active Surveillance Network (FoodNet)
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From page 26... ...
cold 0157:H7 Risk Assessment. Informational memorandum to Wayne Schlosser through Carol Maczka, Director, Risk Assessment Branch, Office of Public Health and Sciences, Food Safety and Inspection Service, USDA, Washington, DC.
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