Decrease of shellfish toxins during the cultivation of toxic scallops in filtered and sterilized seawater

• Published in: Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) Vol. 33; no. 3; pp. 223 - 230_1
• Main Authors: Kikuchi, S. (Muroran Inst. of Technology, Hokkaido (Japan)), Oshima, T, Oshima, Y, Takeuchi, T, Nakamura, T, Tatewaki, M
• Format: Journal Article
• Language: English; Japanese
• Published: Japanese Society for Food Hygiene and Safety 1992
• Subjects: ACUICULTURA; AGUA DE MAR; AQUACULTURE; Chaetoceros septentrionelle; cultivation of scallops; decrease of shellfish toxins; DEGRADACION; DEGRADATION; diatoms; EAU DE MER; ESTERILIZACION; FILTRACION; filtrated and sterilized seawater; FILTRATION; Marine; Patinopecten yessoensis; PEIGNE; SCALLOPS; SEA WATER; shellfish toxins; STERILISATION (GERMES); STERILIZING; TOXINAS; TOXINE; TOXINS; VIEIRA
• ISSN: 0015-6426; 1882-1006
• DOI: 10.3358/shokueishi.33.223

Toxic scallops (Patinopecten yessoensis) were cultivated in tubs in which filtered and sterilized seawater was circulated, with or without supply of planktonic diatoms as feed. The toxicity studies on paralytic shellfish toxins (PST; e. g., saxitoxin, neosaxitoxin, and gonyautoxin family) and diarrhetic shellfish toxins (DST; e. g., okadaic acid and dinophysistoxin family) using the microbial assay method reported previously revealed that both types decreased gradually during the cultivation; the toxicity scores of the former and the latter decreased to 20% of the initial value within a few days and to 30% within two weeks, respectively, when dense cultures of Chaetoceros septentrionelle were supplied as the feed. Because relatively high toxicity scores of both toxins were detected in the excrement of the cultivated scallops, it was assumed that toxins accumulated in tissues, especially in the hepatopancreas, would be discharged through the digestive organs of this specimens during cultivation. When other diatoms such as Skeletonema costatum, Asterionella japonica, Rhabdonema spp. and Thalassiosira spp. were supplied as feed, not only the toxicity but also the amounts of glycogen, free amino acids and free fatty acids decreased, causing a deterioration in quality. These results suggested that the toxicity of toxic scallops could be decreased by cultivation in the absence of toxin producers (e. g., several species of dinoflagellate genus arid bacteria) if an appropriate non-toxic plankton was supplied as feed.