Paralytic shellfish poisoning in Haliotis tuberculata from the Galician coast: geographical distribution, toxicity by lengths and parts of the mollusc

In order to clarify the origin of Paralytic Shellfish Toxins occurring in t he ormers, Haliotis tuberculata, various studies were conducted to describe toxicity distribution by area, length and parts of the mollusc. Ormer toxi city from different locations of the Galician coast had a confidence interv al of 252 +/- 25 mu g STX eq/100 g of meat (mu g of equivalents of saxitoxi n/100 g) by mouse bioassay analyses and 454 +/- 86 mu g STX eq/100 g of mea t by High Performance Liquid Chromatography (HPLC). No value of below 140 m u g STX eq/100 g of meat was detected. No significant differences were obse rved among locations for the values obtained by HPLC, while some difference s were found by mouse bioassay. Toxin composition showed decarbamoylsaxitox in (dcSTX) as the most abundant component (83-100%) with saxitoxin (STX) in a much smaller proportion. Significant differences were observed in the to xin content for the different length groups, toxin content increasing very significantly in the largest ormers, of over 85 mm. Toxin analyses in the d ifferent parts of the molluse by HPLC showed significantly high values for the epithelium of the foot in comparison with the gut and the rest of the m ollusc. They reached 105 x 10(2) +/- 15 x 10(2) mu g of toxin/100 g of epit helium, against 28 +/- 5 mu g of toxin/100 g of gut and 27 +/- 6 mu g of to xin/100 g of muscle. Considering the weight and the quantity of toxin in ea ch part of the ormer, the epithelium carried 2.6 times more toxin than the muscle. (C) 1999 Elsevier Science B.V. All rights reserved.