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From 1993 to 2002, it is estimated that E. coli O157:H7 cost the beef industry an estimated $2.7
billion (Meat & Poultry Magazine, 2003). Historically, the interventions to reduce E. coli
O157:H7 contamination of beef products have targeted the processing segments of the beef
industry. Decreasing the incidence of E. coli O157:H7 involves multiple interventions across all
segments of the beef production chain. This study focuses on identifying critical control points
for pathogen reduction in the production segment of the beef industry. <P>
Previous research indicates that vaccination can reduce the proportion of feedlot cattle shedding
E. coli O157:H7 in the feces (Potter et al., 2004; Peterson et al., 2005). However, the effect of
that vaccine on subsequent hide contamination at harvest has yet to be evaluated. <P>
Additionally, it can be argued that pre-harvest interventions aimed at reducing the carriage and
shedding of E. coli O157:H7 in feedlot cattle will reduce hide contamination at the feedlot, but
not at the packing facility. Transport and lairage may have a considerable impact on cross
contamination of hides. <P>
The objectives of this study were as follows: <br/>
1. Evaluate the effects of vaccinating cattle against type III secreted proteins of E. coli on
the occurrence of E. coli O157:H7 on hides pre- and post-harvest; <br/>
2. Evaluate the effects of transport and lairage on hide contamination.
Findings: A total of 332 steers housed in 42 research pens were studied. A hide sample was collected from steers at the feedlot on the day of shipment for harvest and a second hide sample was collected from the same steers at the processing facility during the harvest process (post-harvest). Vaccination resulted in a 44% reduction in E. coli O157:H7 hide contamination. Vaccination was equally effective at reducing the occurrence of E. coli O157:H7 on hides at the feedlot and at the processing facility. However, cattle hides were more likely to test positive at the processing facility than at the feedlot. These results suggest that pre-harvest intervention strategies can reduce hide contamination at harvest and that the probability for hide contamination may increase during transport and lairage.