Determination of chlorate and chlorite and mutagenicity of seafood treatedwith aqueous chlorine dioxide

The use of chlorine dioxide (ClO2) as a potential substitute for aqueous ch lorine to improve the quality of seafood products has not been approved by regulatory agencies due to health concerns related to the production of chl orite (ClO2-) and chlorate (ClO3-) as well as possible mutagenic/carcinogen ic reaction products. Cubes of Atlantic salmon (Salmo salar) and red groupe r (Epinephelus morio) were treated with 20 or 200 ppm aqueous chlorine or C lO2 solutions for 5 min, and extracts of the treated fish cubes and test so lutions were checked for mutagenicity using the Ames Salmonella/microsome a ssay. No mutagenic activity was detected in the treated fish samples or tes t solutions with ClO2. Only the sample treated with 200 ppm chlorine showed weak mutagenic activity toward S. typhimurium TA 100. No chlorite residue was detected in sea scallops, mahi-mahi, or shrimp treated with ClO2 at 3.9 -34.9 ppm. However, low levels of chlorate residues were detected in some o f the treated samples. in most cases, the increase in chlorate in treated s eafood was time- and dose-related.