Short-time cytotoxicity of mussel extracts: a new bioassay for okadaic acid detection.

Okadaic acid (OA), the main toxin responsible for diarrhoeic shellfish poisoning (DSP) has high cytotoxicity for KB cell cultures (apparent after 3 hr of contact), facilitating rapid detection in contaminated mussels. We developed a method to determine the minimal active concentration (MAC) based on direct microscopic study of toxin-induced changes in cell morphology. A high correlation was found between the MAC of tested extracts and corresponding OA concentrations in mussel hepatopancreas as measured by high performance liquid chromatography. This technique is rapid and reproducible and does not require the use of living animals.