Histamine in Seafood
Histamine fish poisoning (or Scombroid poisoning) is a type of food poisoning caused by elevated levels of histamine being present in the fish. Naturally occurring bacteria in fish produce an enzyme which converts histidine in the fish to histamine. Histamine fish poisoning usually occurs in certain species of fish, such as tuna, sardines, mackerel, swordfish and marlin. Histamine fish poisoning occurs very quickly after eating the fish, usually within 30 minutes to a few hours.
Common signs of histamine fish poisoning include:
- a peppery taste sensation
- tingling of the mouth and lips
- a skin rash
- dizziness and
- itching of the skin.
In some cases nausea, vomiting and diarrhoea may also occur. Symptoms usually last for 4 to 6 hours and rarely exceed one day. It is easily treated with an antihistamine.
Histamine is not destroyed by cooking. Therefore, the best way to keep histamine at a minimum is to ensure proper temperature control. In some cases, low levels of histamine may already be present in the fish when you receive it. To stop it increasing to levels of concern, you should always:
- purchase from reputable suppliers who store the fish on ice or under refrigeration;
- receive product at refrigerated temperatures (<5°C);
- place the fish under refrigeration as soon as it is received;
- keep the fish at refrigerated temperatures when not being used; and
- if the fish is frozen, thaw the fish under refrigeration.
When displaying fish for sale, always ensure there is enough ice on the product and refrigeration units are set at a temperature less than 5°C.