Department of Food Science, Nutrition and Health Promotion, Mississippi State, MS 39762, USA.
Food Microbiol. 2010 Aug;27(5):645-52. doi: 10.1016/j.fm.2010.02.007. Epub 2010 Mar 9.
Catfish skins, intestines, fresh fillets, processing surfaces at different production stages, chiller water and non-food contact surfaces were sampled for Listeria monocytogenes and other Listeria species. Among 315 samples, prevalence of L. monocytogenes, Listeria innocua and a group of Listeria seeligeri-Listeria welshimeri-Listeria ivanovii was 21.6, 13.0 and 29.5%, respectively. No Listeria grayi was detected in this survey. While no L. monocytogenes strains were isolated from catfish skins and intestines, the strains were found with a frequency of 76.7% in chilled fresh catfish fillets and 43.3% in unchilled fillets. L. monocytogenes and Listeria spp. were also detected in fish contact surfaces such as deheading machine, trimming board, chiller water, conveyor belts at different stages, and fillet weighing table. Among L. monocytogenes, 1/2b (47.0%), 3b (16.0%) and 4c (14%) were the predominant serotypes isolated, whereas 4b, 4e, 1/2c and 1/2a were detected at much lower frequencies. Genotype analyses of L. monocytogenes isolates using serotyping, pulsed-field gel electrophoresis (PFGE) and enterobacterial repetitive intergenic consensus (ERIC)-PCR revealed that chiller water represented an important contamination source of L. monocytogenes in the chilled catfish fillets of two processing facilities, whereas fillet weighing table significantly contributed to the catfish fillet contamination of the third facility. This study suggests that L. monocytogenes contamination in the processed catfish fillets originates from the processing environment, rather than directly from catfish. Results from this study can aid the catfish industry to develop a plant-specific proper cleaning and sanitation procedure for equipment and the processing environment designed to specifically target L. monocytogenes contamination.
对鲶鱼皮、内脏、新鲜鱼片、不同生产阶段的加工表面、冷却器水和非食品接触面进行了李斯特菌属和其他李斯特菌属的采样。在 315 个样本中，李斯特菌属、无害李斯特菌属和一组李斯特菌属 seeligeri-Listeria welshimeri-Listeria ivanovii 的流行率分别为 21.6%、13.0%和 29.5%。在本次调查中未检测到 Listeria grayi。虽然在鲶鱼皮和内脏中未分离到李斯特菌属，但在冷藏新鲜鲶鱼片和未冷藏鱼片中的分离频率分别为 76.7%和 43.3%。李斯特菌属和李斯特菌属也在鱼头去除机、修剪板、冷却器水、不同阶段的输送带和鱼片称重台上等鱼类接触表面被检测到。在李斯特菌属中，分离出的优势血清型为 1/2b（47.0%）、3b（16.0%）和 4c（14%），而 4b、4e、1/2c 和 1/2a 的检出频率较低。使用血清分型、脉冲场凝胶电泳（PFGE）和肠细菌重复基因间一致性（ERIC）-PCR 对李斯特菌属分离株进行基因分析表明，冷却器水是两个加工厂冷藏鲶鱼片李斯特菌属的重要污染来源，而鱼片称重台则显著导致第三个加工厂的鲶鱼片污染。本研究表明，加工鲶鱼片李斯特菌属的污染来自加工环境，而不是直接来自鲶鱼。本研究结果可帮助鲶鱼产业为设备和加工环境制定特定于工厂的适当清洁和卫生程序，专门针对李斯特菌属污染。
