U.S. Department of Agriculture, Agricultural Research Service, Russell Research Center, 950 College Station Road, Athens, Georgia 30605, USA.
Prestage Department of Poultry Science, North Carolina State University, Box 7608, Raleigh, North Carolina 27695, USA.
J Food Prot. 2014 Mar;77(3):493-5. doi: 10.4315/0362-028X.JFP-13-320.
Postchill neck skin maceration (NSM) and whole-carcass rinsing (WCR) are frequently used methods to detect salmonellae from processed broilers. These are practical, nondestructive methods, but they are insensitive and may result in false negatives (20 to 40%). Neck skin samples comprise only 4% of the skin from the broiler carcass by weight, while WCR will not detect firmly attached Salmonella organisms and only 7.5% of the rinsate is utilized. Whole-carcass enrichment (WCE) involves incubation of the whole carcass overnight in a preenrichment broth and can recover as few as 8 inoculated Salmonella cells per carcass. The objective of this study was to use NSM, WCR, and WCE sampling to detect naturally occurring Salmonella from the same commercially processed broiler either prechill or postchill. Ten carcasses were obtained prechill and another 10 postchill on each of two replicate days from each of two commercial processing plants. From each carcass, 8.3 g of neck skin was sampled, and then the carcass was rinsed with 400 ml of 1% buffered peptone water. Thirty milliliters was removed and incubated (WCR), and the remaining 370 ml of broth and the carcass were incubated at 37°C for 24 h (WCE). Overall, Salmonella organisms were detected on 21, 24, and 32 of 40 prechill carcasses by NSM, WCR, and WCE, respectively, while 2, 2, and 19 of 40 postchill carcasses were positive by the respective methods. Prechill carcasses were 64% (77 of 120) positive for Salmonella, while postchill carcasses were 19% (23 of 120) positive. Commercial processing reduced the positive-sample prevalence by 45%. Salmonella organisms were detected on 20% (24 of 120) of the samples from plant 1 and 63% (76 of 120) of the carcasses from plant 2. This study demonstrates significant differences in the results for Salmonella prevalence among sampling methods both before and after immersion chilling, as well as between processing plants on days that samples were taken.
后冷却颈部皮肤浸渍（NSM）和全胴体冲洗（WCR）是常用于从加工鸡肉中检测沙门氏菌的方法。这些方法实用且非破坏性，但灵敏度低，可能导致假阴性（20% 至 40%）。颈部皮肤样本仅占肉鸡胴体皮肤重量的 4%，而 WCR 无法检测到牢固附着的沙门氏菌生物体，且仅利用了 7.5%的冲洗液。全胴体富集（WCE）涉及将整个胴体在预富集肉汤中孵育过夜，并且每只胴体可回收多达 8 个接种的沙门氏菌细胞。本研究的目的是使用 NSM、WCR 和 WCE 采样来检测来自同一商业加工鸡肉的自然发生的沙门氏菌，这些鸡肉要么在预冷却前，要么在预冷却后。在两个商业加工厂的两天的每两天，从每个加工厂获得 10 个预冷却的胴体和 10 个后冷却的胴体。从每个胴体中采集 8.3 克颈部皮肤，然后用 400 毫升 1%缓冲蛋白胨水冲洗胴体。取出 30 毫升进行孵育（WCR），其余 370 毫升肉汤和胴体在 37°C 下孵育 24 小时（WCE）。总体而言，通过 NSM、WCR 和 WCE 分别检测到 40 个预冷却胴体中的 21、24 和 32 个存在沙门氏菌生物体，而通过各自的方法，2、2 和 19 个后冷却胴体呈阳性。预冷却胴体中沙门氏菌的阳性检出率为 64%（120 个中的 77 个），而冷却后胴体的阳性检出率为 19%（120 个中的 23 个）。商业加工将阳性样本的流行率降低了 45%。在植物 1 的 120 个样本中的 20%（24 个）和植物 2 的 120 个胴体中的 63%（76 个）中检测到沙门氏菌生物体。本研究表明，在预冷却和冷却后，以及在采样日的不同加工厂之间，沙门氏菌流行率的采样方法存在显著差异。
