Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 9, 2005
Publication Date: September 1, 2005
Citation: Buhr, R.J., Bourassa, D.V., Northcutt, J.K., Hinton Jr, A., Ingram, K.D., Cason Jr, J.A. 2005. Bacteria recovery from genetically feathered and featherless broiler carcasses after immersion chilling. Poultry Science. p. 1499-1504. Interpretive Summary: Empty feather follicles are commonly speculated to harbor bacteria during and after defeathering of poultry carcasses. Numerous publications state that bacteria may become lodged in feather follicles during processing, but none of these publications have provided data to support this statement. To evaluate the role of empty feather follicles on the level of bacteria recovered from the carcass, feathered and featherless broiler chickens were reared together and then processed through immersion chilling. The addition of chlorine to the chiller water was also evaluated on the level of bacteria recovered from the carcass. Genetically featherless carcasses had slightly higher levels E. coli but no difference in recovery of salmonellae and Campylobacter. The addition of chlorine to chiller water lowered the levels of bacteria recovered from carcasses except for Salmonellae. The presence of feathers and empty feather follicles on processed carcasses after immersion chilling appears to have minimal influence on the level of recovery of E. coli, coliforms, and total aerobic bacteria, and no detectable influence on the recovery levels of salmonellae or Campylobacter. These experiments provide additional data that contradicts the assumption that empty feather follicles are a significant harbor for carcass bacteria on processed poultry carcasses. If empty feathers follicles on a carcass do indeed contain bacteria following immersion chilling, it does not appear that the number of these bacteria is significant to impact the bacterial level of the entire carcass.
Technical Abstract: Feathered and featherless (scaleless) sibling broilers were reared and processed together to evaluate the influence of feathers and feather follicles on carcass bacteria recovery after chilling. In each experiment, broilers were inoculated one week prior to processing by oral gavage with a suspension of 10*6 cells / mL salmonellae or Campylobacter. Broilers were stunned, bled, and carcasses were either single-tank or triple-tank scalded, defeathered, eviscerated, and washed. Carcasses were chilled for 45 min in ice and water immersion chillers with or without 20 mg / L chlorine added. Postchill carcass rinsates were evaluated for E. coli, coliforms, total aerobes, and salmonellae or Campylobacter. Following processing and immersion chilling, genetically featherless carcasses had significantly higher counts (by log10 0.35 cfu / 100 mL of carcass rinsate) for E. coli, coliforms, and total aerobes than feathered carcasses. However, there were no significant differences in the prevalence of salmonellae (25%) or Campylobacter (93%) between feathered and featherless carcasses. Recovery of E. coli, coliforms, and total aerobes bacteria were lower for carcasses that were single-tank scalded, and following enrichment, salmonellae were recovered from fewer carcasses subjected to the single-tank (71%) than triple-tank (86%) scalding. Adding chlorine to chiller water significantly decreased carcass bacteria recovery (by log10 0.43 cfu / 100 mL carcass rinsate) for E. coli, coliforms, total aerobes, and Campylobacter, but did not affect salmonellae recovery. The presence of feathers and feather follicles during processing and immersion chilling appears to have minimal influence on the recovery of salmonellae or Campylobacter from carcasses sampled after immersion chilling.