Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium.
Int J Food Microbiol. 2011 Jan 31;145(1):279-86. doi: 10.1016/j.ijfoodmicro.2011.01.009. Epub 2011 Jan 12.
In this study, conducted at five slaughterhouses, individual pigs were sampled and followed up from stunning to cooling down of the carcasses. In this way, Salmonella prevalence and possible risk points were described. At the lairage area, pens were sampled using overshoes. At stunning and bleeding, pigs were individually identified and subsequently swabs were taken of the oral cavity and the carcass after polishing, splitting and forced chilling. Additionally, duodenum, ileum, rectum and mesenteric lymph nodes were extracted and samples were taken of the scalding water. All samples were submitted to Salmonella isolation and Salmonella isolates were serotyped and genotyped by pulsed-field gel electrophoresis (PFGE). Of all samples taken (n = 1953), 14.1% were Salmonella positive. The prevalence of S. in the lairage area varied widely (from 0 to 100%) between the slaughterhouses. Of the sampled pigs (n = 226), 48.2% were positive in at least one sample. Statistical analysis revealed that the contamination of the lairage area was related to a higher amount of positive carcasses after polishing. Furthermore, the contamination of the carcasses after splitting and forced chilling was related to the contamination level of the carcass after polishing. A relation between the outer (carcass) contamination and the inner (gut content and lymph nodes) contamination of a pig could not be established. The predominant serotypes were S. Typhimurium (58.7%) and S. Derby (17.4%). Genotyping revealed 46 different PFGE profiles among the 276 Salmonella isolates. The same genotype at the lairage area as in the oral cavity of the pigs was found in 95%. The results indicate that the lairage area is a primary source of Salmonella in slaughter pigs and that carcass contamination originates from the environment rather than from the pig (inner contamination) itself. It further shows that slaughterhouses vary in their capability of dealing with Salmonella positive pigs. A slaughterhouse specific approach is needed, however, general guidelines should be provided to decrease the contamination level of the lairage area and the slaughter environment.
在这项在五个屠宰场进行的研究中，对个体猪进行了采样，并对其从电击致晕到胴体冷却的过程进行了跟踪。通过这种方式，描述了沙门氏菌的流行情况和可能的风险点。在待宰区，使用套鞋对猪栏进行了采样。在电击致晕和放血过程中，对每头猪进行了单独识别，随后在抛光、分割和强制冷却后，对其口腔和胴体进行了拭子取样。此外，还提取了十二指肠、回肠、直肠和肠系膜淋巴结，并对烫水进行了取样。所有样本均提交给沙门氏菌分离，并用脉冲场凝胶电泳（PFGE）对沙门氏菌分离株进行血清型和基因型分型。在所取的所有样本（n = 1953）中，有 14.1%为沙门氏菌阳性。在屠宰场之间，待宰区的沙门氏菌阳性率差异很大（从 0 到 100%）。在所采样的猪中（n = 226），有 48.2%在至少一个样本中呈阳性。统计分析表明，待宰区的污染与抛光后阳性胴体数量的增加有关。此外，分割和强制冷却后胴体的污染与抛光后胴体的污染水平有关。不能确定猪的外部（胴体）污染与内部（肠道内容物和淋巴结）污染之间的关系。主要血清型为肠炎沙门氏菌（58.7%）和德尔比沙门氏菌（17.4%）。基因分型显示，在 276 株沙门氏菌分离株中存在 46 种不同的 PFGE 图谱。在 95%的情况下，在待宰区和猪口腔中发现了相同的基因型。结果表明，待宰区是屠宰猪中沙门氏菌的主要来源，胴体污染源于环境而非猪本身（内部污染）。这进一步表明，屠宰场在处理沙门氏菌阳性猪的能力上存在差异。需要采取特定于屠宰场的方法，但应提供一般性指南，以降低待宰区和屠宰环境的污染水平。
