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Title: Effects of chlorine or chlorine dioxide during immersion chilling on recovery of bacteria from broiler carcasses and chiller water

item Northcutt, Julie
item Smith, Douglas
item Cox Jr, Nelson
item Ingram, Kimberly
item Buhr, Richard - Jeff
item Richardson, Larry
item Cason Jr, John
item Hinton Jr, Arthur

Submitted to: Poultry Science Association
Publication Type: Abstract Only
Publication Acceptance Date: 4/2/2008
Publication Date: 7/20/2008
Citation: Northcutt, J.K., Smith, D.P., Cox Jr, N.A., Ingram, K.D., Buhr, R.J., Richardson, L.J., Cason Jr, J.A., Hinton Jr, A. 2008. Effects of chlorine or chlorine dioxide during immersion chilling on recovery of bacteria from broiler carcasses and chiller water [abstract]. Poultry Science Association. 87(Suppl.1):40.

Interpretive Summary:

Technical Abstract: A study was conducted to determine the microbiological impact of immersion chilling broiler carcasses with chlorine or chlorine dioxide. Eviscerated, pre-chill commercial broiler carcasses were cut into left and right halves along the keel bone, and each half was rinsed (HCR) in 100 mL of 0.1% peptone for 1 min to establish pre-chill bacterial levels. Halves were then inoculated with 0.1 g of cecal material containing 107 cells per g of gentamicin-resistant Campylobacter (gen-Campy) and 107 cells per g of nalidixic acid resistant-Salmonella (nal-Sal). Paired halves were immersion chilled in either 20 PPM chlorine (pH 7.0) or 3 PPM chlorine dioxide (130 L ice-water per chiller, 0.6 C, 2 RPM). Additional non-inoculated carcasses (NIC) were added to chillers to achieve commercial fill volumes. After 40 min, halves and NIC were removed from chiller and rinsed using the procedure mentioned above. Post-chill HCR were analyzed for numbers of E. coli, coliforms, gen-Campy and nal-Sal. NIC rinses were tested for gen-Campy and nal-Sal. Chiller water samples were evaluated for levels of gen-Campy and Enterobacteriaceae. Numbers of E. coli, Campylobacter and Salmonella found in post-chill HCR were similar for both treatments. Coliform levels were slightly different on halves chilled with chlorine (4.1 log10 cfu/mL rinse) compared to halves chilled with chlorine dioxide (4.4 log10 cfu/mL; P< 0.05). Bacteria were not recovered from chlorinated chiller water; however, gen-Campy (2.3 log10 cfu/mL) and Enterobacteriaceae (3.5 log10 cfu/mL) were found in chlorine dioxide chiller water. When NIC were evaluated, gen-Campy was found on 55% (5/9 positive; 2.0 log10 cfu/mL) of the chlorine-chilled carcasses and 33% (3/9 positive; 2.3 log10 cfu/mL) of the chlorine dioxide-chilled carcasses. Salmonella was not found on NIC chilled with chlorine dioxide, but populations were detected on 22% (2.6 log10 cfu/mL) of those chilled in chlorine. The present study shows that immersion chilling with chlorine and chlorine dioxide removed bacteria from carcass surfaces. Data also showed that chlorinated chiller water had reduced bacterial levels but there was greater carcass cross-contamination with Campylobacter and Salmonella as compared to chlorine dioxide. Key Words: Poultry, immersion chilling, carcass bacteria recovery