Scombroid poisoning or simply scombroid is a common food poisoning caused by eating fish high in histamine levels. It could be cooked, smoked or canned fish which are not processed or stored under proper conditions.

Tuna, mackerel, mahi mahi, sardine, anchovy, herring, bluefish, amberjack, and marlin are the common fishes that causes scombroid. These fishes naturally had histidine. When these fish are stored under inappropriate conditions, bacteria (e.g., Morganella morganii, Escherichia coli, Klebsiella species and Pseudomonas aeruginosa) grows releasing an enzyme histidine decarboxylase and converts the histidine to histamine, which are not eliminated by subsequent cooking, smoking or freezing.

The presence of histamine doesn’t change the smell or appearance of the affected fish. Histamine levels increase due to improper refrigeration before processing or storing fish at room temperature after cooking. Hence the appearance, smell and taste cannot be accounted to find out the affected fish. Histamine is heat stable, so it survive cooking, freezing, canning or smoking.

Symptoms

Onset occurs in 10 to 60 minutes after eating and can last up to 2 days. It include

• flushed skin
• Headache
• Itchiness
• blurred vision
• abdominal cramps
• diarrhea
• bronchospasm
• Respiratory distress

Treatment

Most symptoms of scombroid poisoning is self-limited. In severe cases administration of anthistamine tablet helps to subside the symptoms in 10-15 minutes.

Prevention

• Refrigerating or Freezing the fish soon after it is caught
• Following regulations for allowed histamine levels in fish