Hurd H S, McKean J D, Griffith R W, Wesley I V, Rostagno M H
Pre-Harvest Food Safety and Enteric Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, Iowa 50010, USA.
Appl Environ Microbiol. 2002 May;68(5):2376-81. doi: 10.1128/AEM.68.5.2376-2381.2002.
The objective of this study was to compare, by using identical sample types, the Salmonella enterica prevalences and serovar diversities between pigs necropsied on the farm and those necropsied at the abattoir after transport and holding. We necropsied 567 market weight pigs (>70 kg) from six herds. Pigs were alternately assigned to be necropsied on the farm or at the abattoir. One-half of the group was sent in clean, disinfected trailers to slaughter at a commercial abattoir. After transport (mean distance, 169 km) and 2 to 3 h of holding in antemortem pens, these pigs were necropsied. The 50 pigs remaining on the farm were necropsied the following day. The same sample types and amounts were collected for S. enterica culture at both locations. Results show a sevenfold-higher (P < 0.001) S. enterica isolation rate from pigs necropsied at the abattoir (39.9%; 114 of 286) than from those necropsied on the farm (5.3%; 15 of 281). This difference was also observed for each individual herd. All sample types showed a significantly higher prevalence when comparing abattoir to on-farm collection, respectively: lymph nodes, 9.15 versus 3.6%; cecal contents, 13.6 versus 1.8%; 1 g of fecal matter, 25.2 versus 0.7%. Recovery of additional serovars at the abattoir suggests the pigs are receiving S. enterica from extra-farm sources. This study demonstrates that rapid infection during transport, and particularly during holding, is a major reason for increased S. enterica prevalence in swine. This finding identifies the holding pen as an important S. enterica control point in the pork production chain.
本研究的目的是使用相同的样本类型，比较在农场进行剖检的猪和运输并暂养后在屠宰场进行剖检的猪之间肠炎沙门氏菌的流行率和血清型多样性。我们对来自六个猪群的567头市场体重猪（>70千克）进行了剖检。猪被交替分配在农场或屠宰场进行剖检。该组的一半被用清洁、消毒的拖车送往商业屠宰场屠宰。在运输（平均距离169千米）以及在宰前栏中暂养2至3小时后，这些猪被进行剖检。留在农场的50头猪在第二天进行剖检。在两个地点采集相同类型和数量的样本用于肠炎沙门氏菌培养。结果显示，在屠宰场剖检的猪中肠炎沙门氏菌的分离率（39.9%；286头中有114头）比在农场剖检的猪（5.3%；281头中有15头）高7倍（P<0.001）。在每个单独的猪群中也观察到了这种差异。分别比较屠宰场和农场采集的样本时，所有样本类型的流行率均显著更高：淋巴结，9.15%对3.6%；盲肠内容物，13.6%对1.8%；1克粪便，25.2%对0.7%。在屠宰场发现了更多的血清型，这表明猪正在从农场外的来源感染肠炎沙门氏菌。本研究表明，运输过程中，尤其是暂养期间的快速感染是猪中肠炎沙门氏菌流行率增加的主要原因。这一发现确定了宰前栏是猪肉生产链中一个重要的肠炎沙门氏菌控制点。
