Histamine in Fish

What is histamine and why is it found in fish?

Histamine is a toxic substance produced by certain bacteria when fish start to spoil or ferment into fish products. These bacteria naturally live on the skin, gills, and in the gut of freshly caught fish. The level of histamine in fish depends on the storage time and condition and the amount of histidine amino acid which are naturally higher in fishes like mackerel, sardine, tuna and anchovy. Without proper refrigeration and freezing, histamine can form at any point throughout the supply chain.

What are the risks of histamine?

Eating fish with high levels of histamine may result in intoxication, including skin flushing on the upper half of the body, rash, gastrointestinal complaints, and throbbing headache.

While heat treatment can kill the histamine-producing bacteria, it cannot destroy the histamine that was already formed. Hence, it is crucial to take appropriate measures to minimise histamine formation along the food chain.