There have been several recent reports to the Hospital of individuals suffering from allergic reactions to food.  Following investigations, including histamine analysis, it transpired that those who experienced discomfort had consumed or handled tuna.

Like other fish, the body temperature of tuna warms up soon after capture and bacteria can turn an amino acid called Histidine into Histamine – responsible for many allergic reactions. The symptoms of histamine fish poisoning can occur within minutes to hours after ingestion of toxic fish. Symptoms include:


  • A burning or tingling sensation in and around the mouth
  • Rash and/or swelling over the chest and/or neck
  • Faintness
  • Headache
  • Itchy skin
  • Nausea, vomiting and diarrhoea

Once histamine is formed it cannot be destroyed by freezing, cooking, smoking, curing or canning. The key to controlling histamine is rapid cooling of fish once caught and maintaining a temperature of less than 5 degrees Centigrade until it is ready to cook. The importance of maintaining an unbroken cold environment (cold-chain) from the moment a fish is caught to the time it is put on sale or consumed is vital in preventing harmful bacteria forming.

Fish retailers and members of the public are urged to transport and store fish in appropriate conditions.

The ‘Cold-Chain’

Good hygienic practices on board fishing vessels are vital in this.  Fisherman are expected to establish the first link in the cold chain through judicious care and handling  of fish, as quality lost in the first few hours can never be recovered. They are required to place their catch on ice soon after capture and not to remove their catch from their holding area until such time it can be received by the Fisheries Corporation. The catch should then be transported in sufficient quantities of ice to the Fisheries Cold Store, where it can then be processed and stored in chilled or frozen conditions until sold.

To verify that the cold chain has not been broken up to that point, samples are taken at the Cold Store and analysed for histamine. Inspectors from the Health Directorate also monitor health conditions on boats, on the landing of catches and on the fish process and storage within the Cold Stores.


Environmental Health Section


4 March 2016

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