RIKILT, Institute of Food Safety, Wageningen UR, Akkermaalsbos 2, 6708 WB Wageningen, The Netherlands.
Int J Food Microbiol. 2012 Feb 1;153(1-2):45-52. doi: 10.1016/j.ijfoodmicro.2011.10.013. Epub 2011 Oct 30.
Pork contributes significantly to the public health disease burden caused by Salmonella infections. During the slaughter process pig carcasses can become contaminated with Salmonella. Contamination at the slaughter-line is initiated by pigs carrying Salmonella on their skin or in their faeces. Another contamination route could be resident flora present on the slaughter equipment. To unravel the contribution of these two potential sources of Salmonella a quantitative study was conducted. Process equipment (belly openers and carcass splitters), faeces and carcasses (skin and cutting surfaces) along the slaughter-line were sampled at 11 sampling days spanning a period of 4 months. Most samples taken directly after killing were positive for Salmonella. On 96.6% of the skin samples Salmonella was identified, whereas a lower number of animals tested positive in their rectum (62.5%). The prevalence of Salmonella clearly declined on the carcasses at the re-work station, either on the cut section or on the skin of the carcass or both (35.9%). Throughout the sampling period of the slaughter-line the total number of Salmonella per animal was almost 2 log lower at the re-work station in comparison to directly after slaughter. Seven different serovars were identified during the study with S. Derby (41%) and S. Typhimurium (29%) as the most prominent types. A recurring S. Rissen contamination of one of the carcass splitters indicated the presence of an endemic 'house flora' in the slaughterhouse studied. On many instances several serotypes per individual sample were found. The enumeration of Salmonella and the genotyping data gave unique insight in the dynamics of transmission of this pathogen in a slaughter-line. The data of the presented study support the hypothesis that resident flora on slaughter equipment was a relevant source for contamination of pork.
猪肉在由沙门氏菌感染引起的公共卫生疾病负担方面起着重要作用。在屠宰过程中，猪胴体可能会被沙门氏菌污染。屠宰线上的污染是由携带沙门氏菌的猪在其皮肤或粪便中引起的。另一种污染途径可能是屠宰设备上存在的常驻菌群。为了揭示这两个潜在沙门氏菌来源的贡献，进行了一项定量研究。在 4 个月的时间里，在 11 个采样日期间，沿屠宰线对屠宰设备（开膛器和胴体分割器）、粪便和胴体（皮肤和切割面）进行了采样。大多数在宰杀后直接采集的样本均呈沙门氏菌阳性。在 96.6%的皮肤样本中鉴定出了沙门氏菌，而在直肠中检测到阳性的动物数量较少（62.5%）。在返工站，无论是在切割部位、胴体皮肤还是两者都有，沙门氏菌的流行率明显下降（35.9%）。在屠宰线的整个采样期间，与宰杀后直接相比，在返工站，每头动物的沙门氏菌总数几乎低了 2 个对数级。在研究过程中鉴定出了 7 种不同的血清型，其中以 S. Derby（41%）和 S. Typhimurium（29%）为最主要的类型。在一台胴体分割器中反复出现的 S. Rissen 污染表明，在所研究的屠宰场中存在一种地方性的“室内菌群”。在许多情况下，从单个样本中发现了几种血清型。沙门氏菌的计数和基因分型数据为该病原体在屠宰线中的传播动态提供了独特的见解。本研究的数据支持了这样一种假设，即屠宰设备上的常驻菌群是猪肉污染的一个相关来源。
