Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/2006
Publication Date: 10/1/2006
Citation: Cason Jr, J.A., Buhr, R.J., Hinton Jr, A. 2006. Release of escherichia coli from feathered and featherless broiler carcasses in warm water. Poultry Science. 85:1807-1810.
Interpretive Summary: During poultry processing, carcasses are dipped in tanks of hot water to make it possible to remove the feathers. Large numbers of bacteria are removed at the same time and can move between carcasses. Scald tank designs have been modified over the last few years to try to reduce the chance of bacterial cross-contamination between carcasses. This paper reports numbers of bacteria found in scald water and in carcass rinses in an operating processing plant with several relatively new design features. It appears that multiple-tank scalder designs reduce the numbers of bacteria in scald water and the opportunities for cross-contamination between carcasses via the water.
Technical Abstract: Release of bacteria from individual broiler carcasses in warm water was measured as a model of bacterial contamination of scald water. Immediately after shackling and electrocution, feathered and genetically featherless broiler carcasses (n= 24 of each) were immersed individually in 42° C, air-agitated tap water for 150 s. Although any visible fecal material expelled as a result of electrocution was removed before sampling, carcass condition was typical for market age broilers subjected to 12 hours of feed withdrawal. Duplicate water samples were taken at 10, 30, 70, 110, and 150 s and Escherichia coli counts were determined. Samples of initial tap water and contaminated water approximately 2 minutes after removal of carcasses indicated that E. coli could not be detected in the original water source and that mortality of E. coli in the warm water was negligible. Mean numbers of E. coli released were 6.2 and 5.5 log10 (cfu/carcass) at 150 s for feathered and featherless carcasses, respectively. For both feathered and featherless carcasses, the rate of release of E. coli was highest in the first 10 s and the rate declined steadily during the remaining sampling period. This result is compatible with published reports of sampling of operating multiple-tank scalders indicating that a high proportion of total bacteria in a multiple-tank scalder are in the first scald tank that carcasses enter. Higher numbers of E. coli released from feathered carcasses are probably due to the much greater surface area of contaminated feathers compared to the skin of featherless carcasses.