title: Prevalence and Persistence of Listeria monocytogenes in Ready-to-Eat Tilapia Sashimi Processing Plants.
abstract: 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.
authors.affiliation: Department of Food Science, Fu Jen Catholic University, 510, Zhongzheng Road, New Taipei City 242, Taiwan.
authors.forename: Bang-Yuan
authors.initials: BY
authors.lastname: Chen
authors.affiliation: Experimental Forest, National Taiwan University, 12, Section 1, Chien-Shan Road, Nan-Tou County 557, Taiwan.
authors.forename: Chung-Yi
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Zoonoses Research Center and School of Veterinary Medicine, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei City 106, Taiwan.
authors.forename: Chia-Lan
authors.initials: CL
authors.lastname: Wang
authors.affiliation: Zoonoses Research Center and School of Veterinary Medicine, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei City 106, Taiwan.
authors.forename: Yang-Chi
authors.initials: YC
authors.lastname: Fan
authors.affiliation: Zoonoses Research Center and School of Veterinary Medicine, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei City 106, Taiwan.
authors.forename: I-Ting
authors.initials: IT
authors.lastname: Weng
authors.affiliation: Zoonoses Research Center and School of Veterinary Medicine, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei City 106, Taiwan.
authors.forename: Chung-Hsi
authors.initials: CH
authors.lastname: Chou
mesh_terms: D000818:Animals; D016521:Electrophoresis, Gel, Pulsed-Field; D005506:Food Contamination; D005516:Food Microbiology; D005525:Food-Processing Industry; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification*; D015995:Prevalence; D012703:Serotyping; D017210:Tilapia
keywords: Listeria monocytogenes; Pulsed-field gel electrophoresis; Ready to eat; Sashimi; Tilapia