Here at Marler Clark, we are currently investigating an instance of probable scombroid poisoning for a client that contacted us recently.   We are not contacted by victims of scombroid poisoning with the same frequency as E. coli O157:H7, Salmonella, and Hepatitis A.  Still, we have handled a number of these claims in the past.

According to the CDC, scombroid poisoning is named for a particular family of fish, "Scombridae," which includes tuna and mackerel.  The illness, though, can occur "after ingestion of any dark-fleshed nonscombroid species containing high levels of free histidine."  

The problem stems from improper refrigeration.  When not properly stored, free histidine is broken down to histamine by surface bacteria.

Unlike some foodborne illness that can take many hours, if not days, to take effect, scombroid poisoning begins "minutes to hours after ingestion of the toxic fish."   The CDC identifies symptoms as resembling a  "histamine reaction and frequently include dizziness, headache, diarrhea, and a burning sensation or peppery taste in the mouth. Facial flushing, tachycardia, pruritus, and asthma-like symptoms can also occur."

The FDA has established 50 mg/100g of histamine as a hazardous level in tuna.   Unfortunately, cooking toxic fish will not prevent illness.   The CDC states, therefore, that  the key to prevention of scombroid poisoning is "continuous icing or refrigeration of all potentially scombrotoxic fish from the time they are caught until they are cooked."

Thankfully, symptoms of scombroid poisoning are generally short lived.  Because the illness is associated with improper handling of fish, often at the retail level, outbreaks are generally limited in numbers.   The CDC has previously reported that the median number of cases per outbreak is two.