Chen Bang-Yuan, Wang Chung-Yi, Wang Chia-Lan, Fan Yang-Chi, Weng I-Ting, Chou Chung-Hsi
Department of Food Science, Fu Jen Catholic University, 510, Zhongzheng Road, New Taipei City 242, Taiwan.
Experimental Forest, National Taiwan University, 12, Section 1, Chien-Shan Road, Nan-Tou County 557, Taiwan.
J Food Prot. 2016 Nov;79(11):1898-1903. doi: 10.4315/0362-028X.JFP-16-149.
A 2-year study was performed at two ready-to-eat tilapia sashimi processing plants (A and B) to identify possible routes of contamination with Listeria monocytogenes during processing. Samples were collected from the aquaculture environments, transportation tanks, processing plants, and final products. Seventy-nine L. monocytogenes isolates were found in the processing environments and final products; 3.96% (50 of 1,264 samples) and 3.86% (29 of 752 samples) of the samples from plants A and B, respectively, were positive for L. monocytogenes . No L. monocytogenes was detected in the aquaculture environments or transportation tanks. The predominant L. monocytogenes serotypes were 1/2b (55.70%) and 4b (37.97%); serotypes 3b and 4e were detected at much lower percentages. At both plants, most processing sections were contaminated with L. monocytogenes before the start of processing, which indicated that the cleaning and sanitizing methods did not achieve adequate pathogen removal. Eleven seropulsotypes were revealed by pulsed-field gel electrophoresis and serotyping. Analysis of seropulsotype distribution revealed that the contamination was disseminated by the processing work; the same seropulsotypes were repeatedly found along the work flow line and in the final products. Specific seropulsotypes were persistently found during different sampling periods, which suggests that the sanitation procedures or equipment used at these plants were inadequate. Plant staff should improve the sanitation procedures and equipment to reduce the risk of L. monocytogenes cross-contamination and ensure the safety of ready-to-eat tilapia products.
在两家即食罗非鱼生鱼片加工厂（A厂和B厂）进行了一项为期两年的研究，以确定加工过程中单核细胞增生李斯特菌可能的污染途径。从水产养殖环境、运输水箱、加工厂和最终产品中采集了样本。在加工环境和最终产品中发现了79株单核细胞增生李斯特菌分离株；A厂和B厂样本中分别有3.96%（1264个样本中的50个）和3.86%（752个样本中的29个）单核细胞增生李斯特菌呈阳性。在水产养殖环境或运输水箱中未检测到单核细胞增生李斯特菌。主要的单核细胞增生李斯特菌血清型为1/2b（55.70%）和4b（37.97%）；血清型3b和4e的检出率要低得多。在两家工厂，大多数加工环节在加工开始前就已被单核细胞增生李斯特菌污染，这表明清洁和消毒方法未能充分去除病原体。通过脉冲场凝胶电泳和血清分型揭示了11种血清脉冲型。血清脉冲型分布分析表明，污染是通过加工工作传播的；在工作流程线和最终产品中反复发现相同的血清脉冲型。在不同采样期持续发现特定的血清脉冲型，这表明这些工厂使用的卫生程序或设备不足。工厂工作人员应改进卫生程序和设备，以降低单核细胞增生李斯特菌交叉污染的风险，并确保即食罗非鱼产品的安全。
