EFFECT OF COOKING ON THE CONCENTRATION OF TOXINS ASSOCIATED WITH PARALYTIC SHELLFISH POISON IN LOBSTER HEPATOPANCREAS

The hepatopancreases from lobsters (Homarus americanus) obtained from two locations in eastern Canada (Gaspe and Bay of Fundy) were analysed for paralytic shellfish poisons (PSP) before and after the shellfish were cooked by boiling or steaming. Forty-five lobsters from each loca tion were divided into three groups of 15. Two of the groups were boil ed or steamed while the third was uncooked for comparison purposes. Th e hepatopancreases of all lobsters were individually analysed for tota l PSP toxicity using the standard mouse bioassay procedure. Individual toxins were determined in each sample using a high-performance liquid chromatographic procedure employing pre-chromatographic oxidation of the toxins to form fluorescent derivatives. The results demonstrated t hat boiling or steaming reduced total toxicity (measured as saxitoxin equivalents per hepatopancreas) by approximately 65% compared to value s obtained from raw lobsters. Of the individual toxins studied, saxito xin decreased by about 60% with both the cooking treatments while gony autoxins 2 and 3 (combined) decreased by almost 100% in the Gaspe samp les and by about 90% in the Fundy samples with the same cooking treatm ents. Trace amounts of saxitoxin or gonyautoxins 2 and 3 were detected in some samples of tail or claw meat before or after cooking. In vitr o boiling of raw hepatopancreas for up to 30 min led to no change in t otal or individual PSP concentration, indicating that the toxins in co oked lobster are not removed through chemical decomposition but are le ached out during the loss of water.