DIARRHETIC SHELLFISH POISONING - EVALUATION OF ENZYME-LINKED-IMMUNOSORBENT-ASSAY METHODS FOR DETERMINATION OF DINOPHYSISTOXIN-2

Dinophysistoxin-2 (DTX-2), an isomer of okadaic acid (OA), recently ha s been found in Irish waters, DTX-2 was the predominant toxin during p rolonged infestations in cultivated mussels along the southwest coast of Ireland, Substantial variations in toxin levels may exist both hori zontally and vertically in the water column, The need to take multiple samples and the ethical concern about the use of mammals for routine quality control of shellfish prompted examination of 2 commercially av ailable enzyme-linked immunosorbent assay (ELISA) methods, designed to detect OA, for determination of both OA and DTX-2. One ELISA method ( DSP-Check, Sceti Co, Ltd., (Tokyo, Japan) showed good cross-reactivity (40 +/- 5%) with standard DTX-2, This study showed that both ELISA me thods show good correlation with the liquid chromatographic analysis o f 9-anthryldiazomethane derivatives when OA is the predominant toxin p resent, The sensitivity was also good for OA determination using both methods, which allowed toxin measurement at 10 ng/mL (0.5 ng/well). Th is level is equivalent to 0.03 mu g/g mussel meat. Blank mussel sample s spiked with DTX-2 standards gave a good linear correlation (r = 0.99 7) with this ELISA method when toxin levels were 0.03-0.3 mu g/g musse l meat. This range is appropriate for regulatory control of diarrhetic shellfish poisoning.