title: Trial for quality control in mercury contents by using tail muscle of full-cycle cultured bluefin tuna (Thunnus orientalis).
abstract: Substantial amounts of mercury are usually present in tuna muscle, with levels in excess of 10 times the standard safety value present in some individuals. Inspection of individual fish for mercury content would be desirable but may not be cost-effective. In this study, we tried to establish a low-cost system for checking the mercury content of tuna by using a tail muscle that is usually discarded. The samples used in this experiment were bluefin tuna, cultured in the Fisheries Laboratory of Kinki University (Oshima Experimental Station, Wakayama, Japan). They were raised from eggs spawned in 2002. Ninety-eight individuals, weighing 22.3 to 61.6 kg, were selected between December 2004 and November 2005. In nine individuals, the mercury content of the tail was compared with that of the whole body. The total mercury level was measured using the reduction vaporizing atomic absorption method after acid digestion. Except for the front of the abdomen, where the mercury content was lower (0.490 ppm), the mercury content of other parts of the fish did not differ from that of the tail muscle (0.631 ppm). Therefore, the overall mercury concentration in bluefin tuna could be estimated to be almost the same and/or lower than that of the tail muscle. On the basis of these results, for 1 year we investigated the quantity of mercury in full-cycle cultured bluefin tuna that were shipped. The mercury concentration showed no increase irrespective of increases of body weight.
authors.affiliation: Department of Fisheries, Kinki University, Nakamachi 3327-204, Nara 631-8505, Japan. ando@nara.kindai.ac.jp
authors.forename: Masashi
authors.initials: M
authors.lastname: Ando
authors.forename: Manabu
authors.initials: M
authors.lastname: Seoka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakatani
authors.forename: Tadashi
authors.initials: T
authors.lastname: Tsujisawa
authors.forename: Yuka
authors.initials: Y
authors.lastname: Katayama
authors.forename: Masashi
authors.initials: M
authors.lastname: Nakao
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Tsukamasa
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kawasaki
mesh_terms: D000818:Animals; D003257:Consumer Product Safety; D004784:Environmental Monitoring / Q000379:methods; D005504:Food Analysis; D005506:Food Contamination / Q000032:analysis*; D006801:Humans; D008628:Mercury / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry; D011786:Quality Control; D017747:Seafood / Q000032:analysis* / Q000592:standards; D013623:Tail / Q000737:chemistry; D014018:Tissue Distribution; D014413:Tuna / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury