MALACHITE GREEN AND LEUCOMALACHITE GREEN RESIDUES IN LOCAL AND IMPORTED STRIPED CATFISH, Pangasius hypophthalmus

Malachite green (MG) is commonly used in aquaculture as an antifungal and antiparasitic agent. However, due to its toxicological effects and potential carcinogenesis, the maximum permitted level (MPL) under European Union (EU) regulations of the total MG and its primary metabolite leucomalachite green (LMG) in fish is 2 µg/kg. Hence, a sensitive method for the determination of MG and LMG in local and imported river catfish (Pangasius hypophthalmus) muscle was performed using liquid chromatography tandem mass spectrometry (LC-MS/MS).  Fish samples were purchased from seven local markets. The fish muscles were extracted with acetonitrile using a simple method without the need of solid phase extraction. Results showed that out of 14 samples, 7 samples showed residues ranging from 1.187 to 4.095 µg/kg, and three of the samples contain sum of MG and LMG above 2 µg/kg which exceeds the MPL set by the EU. This indicates that there are residues of MG and LMG in striped catfish available from the market in Malaysia.