Northcutt J K, Berrang M E, Dickens J A, Fletcher D L, Cox N A
USDA Agricultural Research Service, Russell Research Center, PO Box 5677, Athens, Georgia 30604-5677, USA.
Poult Sci. 2003 Jan;82(1):169-73. doi: 10.1093/ps/82.1.169.
A study was conducted to determine effects of bird age at slaughter, feed withdrawal, and transportation on levels of coliforms, Campylobacter, Escherichia coli, and Salmonella on carcasses before and after immersion chilling. Broilers were processed at 42, 49, and 56 d of age after a 12-h feed withdrawal period or a 0-h feed withdrawal period (full fed). At each age, broilers were processed from two commercial farms previously identified as Campylobacter positive. One week before slaughter, broilers were gavaged with nalidixic acid-resistant Salmonella. During bleeding, cotton plugs were inserted into the cloaca of each carcass. Whole-carcass rinses (WCR) were performed before and after immersion chilling with 20 ppm sodium hypochlorite, and rinses were analyzed for coliforms, Campylobacter, E. coli and Salmonella. Log10 counts for coliforms, Campylobacter, and E. coli were (P < 0.05) affected by bird age at slaughter. Feed withdrawal (FW) affected only Campylobacter on carcasses of older broilers (56 d of age). Chilling with sodium hypochlorite resulted in log10 reductions of 1.2, 1.3, 1.4, and 0.5 for coliforms, Campylobacter, E. coli, and Salmonella, respectively. Under the conditions of this experiment, it appears that contamination on the exterior of birds entering the processing facility is critical to carcass bacterial counts. Moreover, carcass bacterial counts did not vary when microbial counts of broilers were comparable. FW may increase prechill carcass counts for E. coli and Campylobacter, but it appears to have no effect on postchill carcass counts when sodium hypochlorite is used in the chilling operation.
进行了一项研究，以确定屠宰时鸡的年龄、停食和运输对浸水冷鲜前后胴体上大肠菌群、弯曲杆菌、大肠杆菌和沙门氏菌水平的影响。肉鸡在42日龄、49日龄和56日龄时进行处理，停食12小时或不停食（全喂）。在每个年龄阶段，从两个先前被确定为弯曲杆菌阳性的商业农场中选取肉鸡进行处理。屠宰前一周，给肉鸡灌喂耐萘啶酸的沙门氏菌。放血过程中，在每个胴体的泄殖腔插入棉球。用20 ppm次氯酸钠进行浸水冷鲜前后，进行全胴体冲洗（WCR），并分析冲洗液中的大肠菌群、弯曲杆菌、大肠杆菌和沙门氏菌。大肠菌群、弯曲杆菌和大肠杆菌的对数值（P < 0.05）受屠宰时鸡的年龄影响。停食仅影响老龄肉鸡（56日龄）胴体上的弯曲杆菌。用次氯酸钠冷鲜导致大肠菌群、弯曲杆菌、大肠杆菌和沙门氏菌的对数值分别降低1.2、1.3、1.4和0.5。在本实验条件下，进入加工设施的鸡体表污染对胴体细菌计数至关重要。此外，当肉鸡的微生物计数相当时，胴体细菌计数没有变化。停食可能会增加大肠杆菌和弯曲杆菌预冷胴体的计数，但在冷鲜操作中使用次氯酸钠时，似乎对冷鲜后胴体的计数没有影响。
