The validity of two HPLC methods and a colorimetric PP2A assay related to the mouse bioassay in quantification of diarrhetic toxins in blue mussels (Mytilus edulis)

Validity of two HPLC methods and a PP2A assay in relation to the mouse bioa ssay for diarrhetic shellfish poisoning (DSP) toxins was evaluated. The mou se bioassay for DSP toxins was performed on a total of 177 mussel samples f rom the Sognefjord, Norway, using diethyl ether in the final step of extrac tion. For fluorimetric HPLC analyses, either 4-bromomethyl-7-methoxycoumari n (BrMMC) or 9-anthryl diazomethane (ADAM) were used for analysis of 48 and 118 of the samples, respectively. The colorimetric PP2A inhibition assay w as performed on all 177 samples that were analysed with the mouse bioassay. When comparing the HPLC-BrMMC, the HPLC-ADAM and the PP2A assays with the mouse bioassay, cut off values of less than or equal to4, 5 and 6 mug okada ic acid (OA) equivalents (eq.)/5 g digestive gland (DG) was used. With refe rence to the results from the mouse bioassay, the total number of failure a nd correct classification by HPLC-ADAM and the PP2A method was compared for the three cut off values. No significant differences between the methods w ere detected. However, all differences were found in favour of HPLC-ADAM. A ll three methods could replace the mouse bioassay in detecting levels of di arrhetic toxins approved internationally for safe consumption of mussels. H owever, HPLC-ADAM seems to be the method of choice. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.