The effect of high-level chlorine carcass drench on the recovery of Salmonella and enumeration of bacteria from broiler carcasses

Authors: Bartenfeld Josselson, Lydia; FLETCHER, DANIEL - University Of Georgia; NORTHCUTT, JULIE - Clemson University; Bourassa, Dianna; Cox Jr, Nelson; Buhr, Richard - Jeff

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2014
Publication Date: 11/27/2014
Citation: Bartenfeld Jossel, L.N., Fletcher, D.L., Northcutt, J.K., Bourassa, D.V., Cox Jr, N.A., Buhr, R.J. 2014. The effect of high-level chlorine carcass drench on the recovery of Salmonella and enumeration of bacteria from broiler carcasses. Poultry Science. 93(11):2893-2899. https://doi.org/10.3382/ps.2014-04051.
DOI: https://doi.org/10.3382/ps.2014-04051

Interpretive Summary: This study was conducted to determine the impact of exposing processed broiler carcasses to a high (ten times higher) concentration chlorinated drench. During each of six replicate trials, carcasses were obtained from a commercial processing plant and chlorine treated carcasses were subjected to a 1 min drench in 500 mL of a 500 ppm chlorine solution, then removed from the bag and rinsed for an additional 1 min in 500 mL of water. Water drenched carcasses were treated the same way except water was used in place of chlorinated-water drench. Control carcasses were not drenched. All carcasses were then subjected to a whole carcass rinse in 450 mL of buffered peptone water, from which 50 mL of the rinsate was removed for enumeration of total aerobic bacteria, Escherichia coli, and total coliforms. The entire carcass was then incubated overnight in the remaining 400 mL of buffered peptone (whole carcass enrichment) for recovery of Salmonella. The levels of bacteria recovered were lower by 0.6 to 0.9 log10 cfu/mL when carcasses were drenched with water versus undrenched control levels. Similarly, the levels of bacteria recovered were lower by 0.5 to 1 log10 cfu/mL when carcasses were drenched with 500 ppm chlorine instead of water. However, there was no significant difference in prevalence of Salmonella between the treatment groups (29% positive for control; 36% positive for water; 38% positive for chlorinated). These results indicate that drenching carcasses with water significantly, but minimally, reduces the numbers of bacteria recovered compared to undrenched carcasses. Similarly, the high concentration chlorine (500 ppm) drench significantly, but minimally, reduced the numbers of bacteria recovered from the chlorine drenched broiler carcasses compared to water drenched carcasses. However, neither drenching carcasses with water or high chlorine had an impact on the prevalence of Salmonella that remain with the carcass. The results of this study confirms the importance of maintaining and replenishing free chlorine for optimal antimicrobial activity, since chlorine at 500 ppm was rapidly utilized within 1 min of exposure to the carcass to < 10 ppm.

Technical Abstract: A study was conducted to determine the bacteriological impact of exposing processed broiler carcasses to a high (10 fold increase) concentration chlorinated drench. During each of 6 replicate trials, eviscerated pre-chill carcasses were obtained from a commercial processing plant and chlorine treated carcasses were subjected to a 1 min drench in 500 mL of a 500 ppm chlorine solution (sodium hypochlorite). Water drenched carcasses were treated the same way except water was used in place of chlorinated water drench. Control carcasses were not drenched. All carcasses were then subjected to a whole carcass rinse (WCR) in 450 mL of buffered peptone water, from which 50 mL of the rinsate was removed for enumeration of total aerobic bacteria (APC), Escherichia coli (EC), and total coliforms (TC). The entire carcass was then incubated overnight at 37ºC (whole carcass enrichment, WCE) for recovery of Salmonella. Levels of bacteria recovered from WCR were lower by 0.6 log10 cfu/mL for APC, 0.8 for EC and 0.9 for TC, when carcasses were drenched with water versus control levels. Similarly, the levels of bacteria recovered from WCR were lower by 1.0 log10 cfu/mL for APC, 0.5 for EC and 0.5 for TC, when carcasses were drenched with 500 ppm chlorine. However, there was no significant difference in prevalence of Salmonella among the treatments (29% positive for control; 26% positive for water; 38% positive for chlorinated). These results indicate that drenching eviscerated carcasses with water or chlorinated water at 500 ppm significantly, but minimally, reduces the numbers of APC, EC, and TC bacteria recovered compared to undrenched carcasses. However, neither drenching carcasses with water or high chlorine had an impact on the prevalence of Salmonella that remain with the carcass as determined by WCE. The results of this study confirms the importance of maintaining and replenishing free chlorine for optimal antimicrobial activity, since chlorine at 500 ppm was rapidly utilized within 1 min of exposure to the carcass to < 10 ppm.