Bioavailability of Hg and Se from seafood after culinary treatments

The present study aims to evaluate the bioavailability of Hg and Se in blacktip shark, Asian tiger shrimp and squid tube samples after three culinary treatments: boiling, frying and sautéing. Cooked and uncooked samples were evaluated for each seafood species with and without addition of spices (salt, lemon juice and garlic). After each culinary treatment, the seafood samples were freeze-dried, ground and stored for further analysis. The following parameters were evaluated and optimized: sample mass, sample size, cooking time and temperature. The determination of total concentration of Hg and Se was carried out by ICP-MS/MS. In order to minimize the memory effects for Hg, an integrated sample introduction system (ISIS) coupled with ICP-MS/MS was used employing water, 5% HNO3 and 5 mg L−1 Au for the washing steps. No significant losses of Se in the seafood were observed after culinary treatments with and without spices. For Hg, losses for blacktip shark and Asian tiger shrimp were observed after boiling, frying and sautéing procedures (14 to 33%) with and without spices. Blacktip shark showed the highest Hg concentration, about 245% higher than the maximum level recommended by the official health organizations. The Se/Hg molar ratio was also determined in all samples and blacktip shark showed a Se/Hg molar ratio < 1 that can be considered to be a higher risk to health. Mercury presented a significant change in bioavailability due to the influence of all culinary treatments. However, the bioavailability of Se from cooked samples proved to be independent of the culinary treatment.