|Byrd Ii, James|
Submitted to: Zoonoses and Public Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2009
Publication Date: 12/1/2009
Publication URL: http://handle.nal.usda.gov/10113/57250
Citation: Volkova, V.V., Bailey, R.H., Rybolt, M.L., Dazo-Galarneau, K., Hubbard, S.A., Magee, D., Byrd II, J.A., Wills, R.W. 2009. Inter-relationships of Salmonella status of flock and grow-out environment at sequential segments in broiler production and processing. Zoonoses and Public Health. 57:463-475. Interpretive Summary: Effective Salmonella control in chickens is important to both consumers and those who grow the birds. We looked at the bacteria Salmonella, recoverd from different sample types taken from the chickens and their environment. Chickens were examined for Salmonella before being transported for slaughter at three different areas, and we found chicks that had Salmonella at slaughter if they had Salmonella when they hatched from the egg. Birds that had Salmonella on their feathers and on the floor were more likely to have Salmonella in their gastrointestinal tract than birds that did not have Salmonella on their feathers. In addition, Salmonella on the feathers of birds on the farm and at the slaughter plant, also increased the likelihood of one bird, multiple carcasses being contaminated with Salmonella at the end of slaughter. Birds that have Salmonella in their crop before they leave the farm had higher likelihood of having Salmonella at the end of slaughter than birds that did not have Salmonella. The best indicator that birds will have Salmonella at the end of slaughter was to find the pine litter on the floor positive for Salmonella. However, Salmonella was found on the the pine litter when the birds were present and not prior to the arrival of the birds. Differences among the farms, but not the companies, appear to be due to the differences in Salmonella status of chickens prior to leaving the farm, upon arrival at the slaughter plant, and immediately at the end of the slaughter process.
Technical Abstract: Effective Salmonella control in broilers is important from the standpoint of both consumer protection and industry viability. We investigated associations between Salmonella recovery from different sample types collected at sequential stages of one grow-out from the broiler flock and production environment. Broiler flock Salmonella status at the end of the grow-out cycle, as measured by three different sample types, was associated with flock status upon delivery from the hatchery, but not with prior contamination of the grow-out environment. Higher external contamination of the birds and the litter at the end of the grow-out was associated with increased likelihood of Salmonella in the ceca of birds arriving for processing. Higher external contamination of the birds in grow-out and at arrival for processing also led to increased likelihood of contaminated carcasses entering the immersion chill tank. A certain proportion of Salmonella-positive crops may be established in broiler flocks at grow-out and contribute to an increased frequency of birds with Salmonella-positive crops arriving at the plant, which in turn can lead to higher likelihood of post-chill Salmonella-contaminated carcasses. The best predictors of broiler flock Salmonella status post-chill in this study were the frequency of Salmonella in the litter at harvest time and prior to placement. Likelihood of Salmonella contamination of the litter at harvest was associated with Salmonella status of the broiler flock, but not with the status of the litter prior to the placement. Variability among the grow-out farms, but not that among production complexes or companies, appeared to contribute to variability in Salmonella status of the broiler flocks at the end of the grow-out, upon arrival at the plant, and immediately before and after the immersion chill tank.