Histamine (scombroid) fish poisoning, Food Safety Glossary
An illness caused by eating fish that has built up high levels of histamine because it was not kept cold enough after being caught.
An illness caused by eating fish that has built up high levels of histamine because it was not kept cold enough after being caught. Histamine fish poisoning, also called scombroid poisoning, happens when certain fish are not chilled properly after being caught, allowing natural bacteria to convert compounds in the flesh into histamine. When someone eats fish with high histamine levels, they can react as though having an allergic reaction, even though it is a chemical poisoning rather than a true allergy. It is most associated with fish that naturally have high levels of the precursor compound, including tuna, mackerel, mahi-mahi, sardines, anchovies and similar species. Symptoms usually come on quickly, often within minutes to a couple of hours of eating, and include flushing of the face, a rash, headache, sweating, a peppery or metallic taste, palpitations, nausea and diarrhoea. Most people recover within a day, and antihistamines can help, but reactions can be more severe in some individuals. A key point is that histamine is heat-stable, so once it has formed in poorly chilled fish, cooking does not destroy it and the fish cannot be made safe. The only reliable control in an Australian food business is keeping susceptible fish cold from catch to plate, because histamine forms when fish warms up and cannot be removed later. Tuna, mackerel and similar species should be received cold, checked on delivery, and kept at 5 degrees or below, or well frozen, with minimal time out of refrigeration during preparation. Rejecting fish that arrives warm, or that has an off, sharp or ammonia-like smell, is important. Because histamine is not destroyed by cooking and does not always make the fish look or smell obviously spoiled, cold-chain discipline and supplier reliability are the main safeguards. Businesses should buy from reputable suppliers with good temperature control, monitor and record fridge and delivery temperatures, and train staff to handle these fish quickly and keep them chilled. Any fish suspected of temperature abuse should be discarded rather than served. A supplier delivers fresh tuna that has been sitting in a warm van, and the kitchen accepts it without checking the temperature. During the day the tuna is left out on the bench between prep tasks, letting histamine build up. That evening several diners who order the seared tuna flush, break out in a rash and feel unwell within an hour. Because cooking does not destroy histamine, searing did not help. Keeping the tuna cold throughout would have prevented it.
Frequently asked questions
Which fish cause histamine poisoning?
Fish that naturally have high levels of the precursor compound, such as tuna, mackerel, mahi-mahi, sardines and anchovies, are the usual cause. Histamine builds up in these fish when they are not kept cold enough after being caught.
What are the symptoms?
Symptoms appear quickly, often within minutes to a couple of hours, and include facial flushing, rash, headache, sweating, a peppery taste, palpitations, nausea and diarrhoea. It can look like an allergic reaction but is a chemical poisoning.
Does cooking make histamine-affected fish safe?
No. Histamine is heat-stable, so once it has formed in poorly chilled fish, cooking, canning or freezing will not destroy it. The fish cannot be made safe and must be discarded.
How can it be prevented?
Keep susceptible fish cold from catch to plate at 5 degrees or below, check temperatures on delivery, minimise time out of refrigeration, and buy from reputable suppliers. Reject fish that arrives warm or smells sharp or ammonia-like.
Is histamine poisoning the same as a fish allergy?
No. It causes allergy-like symptoms but is a chemical poisoning from histamine that formed in the fish, not an immune reaction to the fish itself. Anyone can be affected if the fish contains enough histamine.
