Food Safety Focus (217th Issue, August 2024) – Article 3

Methylmercury in Fish and Food Safety

Recently, a sample of imported swordfish sashimi obtained from an online shop was detected with methylmercury at a level exceeding the legal limit under the food surveillance programme. The affected product was removed from shelves.

Methylmercury is the organic form of mercury which accumulates along the food chain. Excessive intake of methylmercury can affect foetal brain development, and affect vision, hearing, muscle co-ordination and memory in adults. Though the levels of methylmercury in most fish are low, the World Health Organization is of the opinion that consuming predatory fish species is the main source of mercury intake. Predatory fish such as tuna, shark and swordfish may contain high levels of mercury.

To minimise excessive exposure to metal contaminants in food, groups susceptible to the adverse effects of methylmercury such as pregnant women, women planning a pregnancy and young children should avoid eating predatory fish. The trade should inform customers of the fish types and the ingredients of fish products for sale.