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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Poultry Microbiological Safety and Processing Research Unit » Research » Publications at this Location » Publication #316256
Title: Prevalence and serogroup diversity of Salmonella for broiler neck skin, whole carcass rinse, and whole carcass enrichment sampling methodologies following air or immersion chilling

Author
item Bourassa, Dianna
item HOLMES, JESSICA - University Of Georgia
item CASON, JOHN - Retired ARS Employee
item Cox Jr, Nelson
item Rigsby, Luanne
item Buhr, Richard - Jeff

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2015
Publication Date: 11/1/2015
Citation: Bourassa, D.V., Holmes, J., Cason, J.A., Cox Jr, N.A., Rigsby, L.L., Buhr, R.J. 2015. Prevalence and serogroup diversity of Salmonella for broiler neck skin, whole carcass rinse, and whole carcass enrichment sampling methodologies following air or immersion chilling. Journal of Food Protection. 78(11):1938-1944.

Interpretive Summary: The purpose of this study was to evaluate broiler carcass sampling procedures for Salmonella detection and serogroup (grouping of Salmonella serotypes having one or more antigens in common) from the same carcass following either air or immersion (ice/water) chilling. The sampling methods were neck skin (NS, flap of skin covering the base of neck), whole carcass rinse (WCR, shaking the entire carcass in 400 mL of liquid and collecting 30 mL), and whole carcass enrichment (WCE, after shaking the entire carcass incubating the carcass within the 400 mL of liquid). Commercially processed and eviscerated broiler carcasses were collected from a commercial processing plant. In the first experiment carcasses were air chilled at 4C without water, while in the second experiment carcasses were immersion chilled with or without added chlorine for 40 minutes. Following air chilling (without any antimicrobials applied), Salmonella was detected on 78% NS and 89% WCE samples. Only a single Salmonella serogroup was detected from each of 13 positive NS samples and two serogroups were detected on 1 NS sample. Only a single Salmonella serogroup was detected from 13 positive WCE samples while double serogroups were detected on 3 positive WCE samples. Following immersion chilling without chlorine, Salmonella was detected on 38% NS, 45% WCR, and 100% WCE samples. Without chlorine, the 15 positive NS had 14 single and 1 double serogroup sample. Only 1 Salmonella serogroup was detected from WCR samples following immersion chilling. From the 40 positive WCE samples, 23 had a single, 14 had double, and 3 had triple serogroups detected. Following immersion chilling with chlorine, Salmonella was detected on 35% NS, 0% WCR, and 90% WCE samples. With chlorine, the 14 positive NS samples had 11 single and 3 double serogroups. No Salmonella serogroups were detected from WCR samples following immersion chilling with chlorine. With chlorine, the 36 positive WCE samples had 21 single and 15 double serogroups. Both NS and WCE sampling methodologies yielded similar Salmonella recovery levels and serogroup diversity following air chilling of the carcasses. However, following immersion chilling of the carcasses with or without chlorine, WCE sampling yielded significantly more Salmonella positive carcasses and serogroup diversity than either NS or WCR methodologies. Sampling poultry carcasses for Salmonella using WCE is a research methodology with the theoretical ability to detect very low numbers of Salmonella (eight Salmonella cells/carcass or part). However, using WCE sampling for Salmonella surveillance of poultry products is not practical, since WCE utilization of the entire carcass or part, thereby leaving no part of the chicken carcasses for consumption.

Technical Abstract: The purpose of this study was to evaluate neck skin (NS), whole carcass rinse (WCR), and whole carcass enrichment (WCE) sampling procedures for Salmonella isolation and serogroup from the same broiler carcass following either air or immersion chilling. Commercially processed and eviscerated broiler carcasses were collected from a commercial processing plant, individually bagged, and transported to the pilot processing plant. For Experiment 1, carcasses were air chilled to 4°C. In Experiment 2 carcasses were immersion chilled with or without 20 mg/L free chlorine. Following air chilling, Salmonella was detected on 78% NS and 89% WCE samples. Only a single Salmonella serogroup was detected from each of 13 positive NS samples while double serogroups were detected on 1 NS sample. Only a single Salmonella serogroup was detected from 13 positive WCE samples while double serogroups were detected on 3 positive WCE samples. Following immersion chilling without chlorine, Salmonella was detected on 38% NS, 45% WCR, and 100% WCE samples. Without chlorine, the 15 positive NS had 14 single and 1 double serogroup sample. Only 1 Salmonella serogroup (C3) was detected from WCR samples following immersion chilling. From the 40 positive WCE samples, 23 had a single, 14 had double, and 3 had triple serogroups detected. Following immersion chilling with chlorine, Salmonella was detected on 35% NS, 0% WCR, and 90% WCE samples. With chlorine, the 14 positive NS samples had 11 single and 3 double serogroups. No Salmonella serogroups were detected from WCR samples following immersion chilling with 20 mg/L free chlorine. The 36 positive WCE samples had 21 single and 15 double serogroups. NS and WCE sampling methodologies yielded similar (a = 0.05) prevalence and serogroup diversity following air chilling. However, following immersion chilling with or without chlorine, WCE sampling yielded significantly higher (a = 0.05) prevalence and serogroup diversity than either NS or WCR methodologies.