Shellfish Poisoning

The most common form of shellfish poisoning in Florida results from the consumption of raw shellfish that has been contaminated by bacteria or a virus.  Symptoms of this type of poisoning generally involve several days of gastrointestinal upset and sometimes fever. 

Shellfish worldwide can also be contaminated with naturally occurring marine toxins.  These rare marine toxin-related illnesses include: Neurotoxic Shellfish Poisoning or “NSP”; Paralytic Shellfish Poisoning or “PSP”; and Amnesic Shellfish Poisoning or “ASP”.  All of these illnesses can be caused by eating clams, mussels or oysters that have been exposed to the micro-algae responsible for red tides or other harmful algal blooms (HABs).  Symptoms can appear within minutes to several hours after contaminated shellfish is eaten, and may include: tingling sensations in the lips or extremities, unusual sensations of hot and cold, vomiting, diarrhea, and sometimes a loss of coordination that can result in staggering or difficulty walking.  The symptoms usually last several days and then go away, but the elderly, children and people who have other health problems can experience more serious illness.  Sometimes, particularly with PSP and ASP, difficulty breathing can occur.  If you believe you have become sick from eating shellfish, contact your doctor immediately and, if possible, save some of the shellfish for your doctor to send for testing.

The Florida Department of Agriculture and Consumer Services conducts an excellent monitoring program that routinely tests shellfish beds and closes any determined to be unsafe.  Detailed shellfish bed closure information is available at http://www.floridaquaculture.com/, click on ‘Daily Reports’.  Most reported cases of shellfish poisoning in Florida are the result of individuals harvesting shellfish during a restricted period.  Commercial shellfish operations that supply restaurants are careful to avoid closed areas, and monitor their harvests routinely for the presence of toxins.  Unfortunately, there is no method for the home testing of shellfish that is approved by the FDA, and cooking or freezing does not destroy marine toxins.  Thoroughly cooking shellfish is an effective way of minimizing bacteria and viral contamination, and remains the best way to protect yourself against the majority of shellfish-related illnesses.

For more information about how to safely enjoy Florida fish and shellfish go to http://www.floridamarine.org/ , or call the Florida Department of Health Aquatic Toxins Program at (850) 245-4299.