Dye Residue Analysis in Raw and Processed Aquaculture Products: Matrix Extension of AOAC INTERNATIONAL Official Method 2012.25.

Background : Triphenylmethane dyes and metabolites are known or suspected mutagens and are prohibited in animals intended for human consumption. Despite toxicity, triphenylmethane dyes are used illegally as inexpensive treatments for fungal and parasite infections in aquatic animals. Objective: AOAC INTERNTIONAL Official Method 2012.25 for the LC-MS/MS determination of malachite green, crystal violet, brilliant green, and metabolites leucomalachite green and leucocrystal violet in seafood products was previously validated for finfish (trout, salmon, catfish, and tilapia) and shrimp, but had not been fully validated for other types of aquacultured products such as eel, molluscan shellfish, or frog or for processed seafoods. Methods: Method 2012.25 was applied to a wide scope of raw and processed aquaculture products including Arctic char, barramundi, eel, frog legs, hybrid striped bass, pompano, scallops, seabream, smoked trout, dried shrimp, and highly processed canned eel and dace products. The canned products contained oil, salt, sugar, flavorings, spices, sauces, and/or preservatives. Results: Dyes and metabolites were recovered with >85% accuracy and precision generally <20% relative standard deviation. The method detection limit was ≤0.60 μg/kg and LOQ was <1.0 μg/kg. Compounds were identified in 99% of 330 fortified and incurred samples. Conclusions: This study supports the use of Method 2012.25 for triphenylmethane dye residue analysis in a wide variety of aquacultured and seafood products. Highlights: Method 2012.25 performed well with results consistent with previous validation studies, regardless of presence of additional food ingredients or the type of processing.