Departamento de Medicina Veterinária Preventiva, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
J Food Prot. 2012 Sep;75(9):1580-8. doi: 10.4315/0362-028X.JFP-11-515.
This study was conducted to assess the dissemination of Salmonella clonal groups in slaughterhouses that received batches of Salmonella -positive pigs and used different routine processing procedures. Eight serial sampling sessions were conducted in three slaughterhouses (A, B, and C). Blood was collected randomly (n = 25) from each batch of pigs and processed for serology. Carcasses (n = 12) were identified and sampled after dehairing, after singeing, after evisceration, and before chilling. A section of cecum also was collected. Salmonella isolates were submitted to pulsed-field gel electrophoresis. The overall seroprevalence of Salmonella was 80.6% (316 of 392 samples), and cecal contents were positive for Salmonella in 23.8% (26 of 109) of the pigs sampled. Carcasses after dehairing had a significantly higher prevalence of Salmonella (P = 0.004) and the highest Salmonella levels (median = 0.26 log CFU/300 cm(2)). The singeing step significantly affected the Salmonella status of the carcasses (P = 0.001); however, the efficacy of singeing differed among slaughterhouses. In the prechilling step, 14.7% (16 of 109) of the carcasses were positive for Salmonella. Salmonella pulsotypes found on the prechill carcasses were also found in the lairage, in the cecal contents, and on carcasses after dehairing, suggesting that the main source of contamination was the slaughter process before singeing. Slaughterhouse C was the most likely (odds ration [OR] = 6.51) to have pigs carrying Salmonella in the gut, and slaughterhouse B was the most likely (OR = 14.66) to have contaminated carcasses at the prechilling step. These findings indicate that the procedures adopted in slaughterhouse B contributed to the spread of Salmonella strains. In contrast, in slaughterhouse C the Salmonella strains carried by the pigs or found in the lairage were not recovered from prechilled carcasses, validating the effectiveness of the slaughterhouse interventions. These results indicate that an effective slaughter process can help decrease the number of Salmonella-positive carcasses in slaughterhouses that receive Salmonella-positive pig batches.
本研究旨在评估在接收阳性猪批次并使用不同常规处理程序的屠宰场中沙门氏菌克隆群的传播情况。在三个屠宰场（A、B 和 C）进行了八次连续采样。从每批猪中随机采集血液（n=25）并进行血清学处理。在去毛、燎毛、去内脏和预冷后对胴体（n=12）进行鉴定和采样。还采集了一段盲肠。沙门氏菌分离株进行脉冲场凝胶电泳。沙门氏菌的总血清流行率为 80.6%（316 份样本中的 316 份），在 23.8%（109 份样本中的 26 份）采样的猪中盲肠内容物呈沙门氏菌阳性。去毛后的胴体沙门氏菌流行率显著更高（P=0.004），沙门氏菌水平最高（中位数=0.26 log CFU/300 cm²）。燎毛步骤显著影响胴体的沙门氏菌状态（P=0.001）；然而，不同屠宰场的燎毛效果不同。在预冷步骤中，14.7%（109 份样本中的 16 份）的胴体呈沙门氏菌阳性。在预冷胴体上发现的沙门氏菌脉冲型也在畜栏、盲肠内容物和去毛后的胴体上发现，表明污染的主要来源是燎毛前的屠宰过程。屠宰场 C 最有可能（优势比[OR]=6.51）在肠道中携带沙门氏菌的猪，屠宰场 B 最有可能（OR=14.66）在预冷步骤中污染胴体。这些发现表明，屠宰场 B 采用的程序助长了沙门氏菌菌株的传播。相比之下，在屠宰场 C，从预冷胴体上未回收猪携带或在畜栏中发现的沙门氏菌菌株，验证了屠宰场干预措施的有效性。这些结果表明，有效的屠宰过程有助于减少接收阳性猪批次的屠宰场中阳性胴体的数量。
