title: Decontamination of Vibrio parahaemolyticus in fish by washing with hygienic seawater and impacts of the high level contamination in the gills and viscera.
abstract: The effect of washing in Vibrio parahaemolyticus contaminated and hygienic seawater on fish, and the frequency and level of natural V. parahaemolyticus contamination in fish were investigated. In the first experiment, live horse mackerel was experimentally kept in seawater artificially contaminated with V. parahaemolyticus. After washing in contaminated and hygienic seawater, the contamination in fish was quantitatively analyzed. Washing fish in the seawater contaminated with V. parahaemolyticus increases the contamination level on the surface and in the gills of the fish. Washing in hygienic seawater was effective in reducing the contamination in fish and cutting board surfaces, but not in the gills or viscera. In the second experiment, natural V. parahaemolyticus contamination in various fish caught by us was analyzed. V. parahaemolyticus was detected in 6 of 28 gill samples and 10 of 28 viscera samples of naturally contaminated fish. The means of V. parahaemolyticus level on gills were 3.3 and 3.9 log cfu/g, and those in viscera were 2.6 and 4.4 log cfu/g by culture method and a real-time PCR assay, respectively. These results indicate that the gills and viscera are able to spread the pathogens to fish meat as well as fish surface contamination by washing in the contaminated seawater. Washing with hygienic seawater and control of contamination from gills and viscera are critically important to prevent V. parahaemolyticus infections.
authors.affiliation: Division of Microbiology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan. ykudo@nihs.go.jp
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Hara-Kudo
authors.forename: Susumu
authors.initials: S
authors.lastname: Kumagai
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Konuma
authors.forename: Norinaga
authors.initials: N
authors.lastname: Miwa
authors.forename: Takashi
authors.initials: T
authors.lastname: Masuda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ozawa
authors.forename: Tokuhiro
authors.initials: T
authors.lastname: Nishina
mesh_terms: D000818:Animals; D017756:Aquaculture / Q000379:methods; D015169:Colony Count, Microbial / Q000662:veterinary; D003666:Decontamination / Q000379:methods*; D005393:Fish Diseases / Q000382:microbiology* / Q000517:prevention & control / Q000628:therapy*; D005880:Gills / Q000382:microbiology; D010473:Perciformes; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012623:Seawater / Q000737:chemistry / Q000382:microbiology; D014735:Vibrio Infections / Q000517:prevention & control / Q000628:therapy / Q000662:veterinary*; D014736:Vibrio parahaemolyticus / Q000302:isolation & purification*; D014781:Viscera / Q000382:microbiology