Katzav Marianne, Hyvönen Paula, Muje Petri, Rantala Leila, Von Wright Atte
Institute of Applied Biotechnology, Nutrition and Food Biotechnology, University of Kuopio, Box 1627, FI-70211 Kuopio, Finland.
J Food Prot. 2006 Jun;69(6):1443-7. doi: 10.4315/0362-028x-69.6.1443.
The aim of this study was to find sources of Listeria monocytogenes contamination in fish products from a fish farm. The occurrence of L. monocytogenes also was compared in two freshwater fish farms with different types of fishponds. Samples collected from chilled rainbow trout (Oncorhynchus mykiss) and the slaughterhouse environment did not contain L. monocytogenes, but Listeria innocua was found in two samples from the slaughterhouses. Ten isolates of L. monocytogenes were discovered in sediment and water samples from farming tanks and earth ponds. Further characterization by serovar revealed the same serovar (1/2a) for all the isolates. Pulsed-field gel electrophoresis was used to divide the isolates into five different pulsotypes, three of which have been identified previously in fish products on the retail market. This finding supports the assumption that the primary production, and probably the raw fish, is a source of Listeria contamination in fish products. Some of the isolates were associated with a certain type of fishpond, indicating the need for hygienic analysis of the suitability of different types of farming ponds.
本研究的目的是找出某养鱼场鱼产品中单核细胞增生李斯特菌的污染源。同时，对两个拥有不同类型鱼塘的淡水养鱼场中单核细胞增生李斯特菌的出现情况进行了比较。从冷藏虹鳟鱼（Oncorhynchus mykiss）和屠宰场环境采集的样本中未检测到单核细胞增生李斯特菌，但在屠宰场的两个样本中发现了无害李斯特菌。在养殖池和土池的沉积物及水样中发现了10株单核细胞增生李斯特菌。通过血清型进一步鉴定发现，所有分离株均为同一血清型（1/2a）。脉冲场凝胶电泳将分离株分为五种不同的脉冲型，其中三种此前已在零售市场的鱼产品中鉴定出。这一发现支持了初级生产环节，可能还有生鱼，是鱼产品中李斯特菌污染来源的假设。部分分离株与特定类型的鱼塘有关，这表明需要对不同类型养殖池塘的适宜性进行卫生分析。
