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Food Safety Savvy: Maricos el Veneno (Poison From The Sea) 

By Jean Dible, GA Food Safety Professionals

Your Food Safety Connection

Millions or perhaps billions of people throughout the world eat seafood on a regular basis, so what is the big deal about eating seafood, and what makes this wonderful protein food potentially dangerous? The BIG DEAL or problem is that certain types of seafood can cause a lot of human suffering, if the seafood is not cooked or frozen properly, or the seafood that is eaten comes from a Red Tide area of the world. For General Aviation employees, ordering or eating seafood before or during a flight or during down time on a trip can be risky, at best! Off duty and home-based employees should also be cautious of most seafood at any time or place that the seafood is cooked or eaten. Seafood is also a high liability food for restaurants or catering companies selling seafood to customers. The major problems with fresh fish, shellfish, and crustacean (lobsters, crabs & shrimp) are: parasites (round worms); toxins (poisons), and mercury (poison).


Parasites are living organisms that need a host to survive, and many types of parasites infect animals, which are usually pigs, cows, chickens and fish. Fish parasites are called Anisakis simplex, which are round worm-like creatures found in certain fish and shellfish. It is critical to cook certain fish and shellfish properly (minimum temperature of 145 degrees for 15 seconds) in order to kill off the worm-like parasites and their eggs (larva). An illness causing a lot of human suffering from the seafood parasites can be non-invasive, which would cause a person to cough the parasites (worms) from the body. If the parasite worms become invasive in a human body, the worms actually penetrate the lining of the stomach and/or small intestine system and must be surgically removed. The fish most commonly associated with Anisakis simplex parasites are: Cod, Halibut, Herring, Mackerel, & Pacific Salmon. The most common symptoms for parasite worms are: tingling in the throat, coughing up worms, intense stomach pain, vomiting, nausea, and diarrhea.

BEWARE, if you are a sushi eater! In order for fish to be used safely in sushi, the fish has to be frozen for a minimum of seven days at a temperature of (-4 degrees F.) in order to kill off the parasites and their larva. Purchasing sushi from a catering company is not a good idea because the sushi will generally be sub-contracted from another source. If you do not always know how safe your food supply is from your catering company, how can you possibly track the safety of sushi that is prepared at a different location from your primary food supplier? In addition to the raw fish being a problem in sushi, the rice in sushi is also a potential danger. The bacillus cereus bacteria in rice can also rear its ugly head and cause a lot of pain and human suffering in humans if the sushi was not maintained at a temperature below 41 degrees F.

SHELLFISH TOXINS: As with fish, shellfish can also have a build-up of toxins, which can also cause a lot of human suffering. Again, the shellfish toxins have to do with The Red Tide, or toxic marine algae that the shellfish filter from the water. Toxins in shellfish also cannot be smelled or tasted, and are not destroyed by freezing or cooking. It is critical to know where your shellfish come from and that they were harvested from waters free of the toxic algae. There are three types of toxins in shellfish, which are:

-- Amnesic Shellfish Poisoning (Domoic acid toxin)

-- Neurotoxic Shellfish Poisoning (Brevetoxin)

-- Paralytic Shellfish Poisoning (Saxitoxin)

AMNESIC SHELLFISH POISONING is found in shellfish in the coastal cold waters of the Pacific Northwest and the east coast of Canada. These shellfish usually include Clams, Mussels, Oysters, and Scallops. The severity of the symptoms from the toxin in these shellfish depends on the health of the individual and amount of toxin consumed.

Symptoms usually include:

First Symptoms:

Later Symptoms: (possibly)




Memory loss

Abdominal pain






NEUROTOXIC SHELLFISH POISONING, which is the Brevetoxin is found in warmer waters. Those waters usually include the west coast of Florida, the Gulf of Mexico and the Caribbean Sea. Again, poisonous algae are the enemy as the shellfish filter these algae from the water. These shellfish include Clams, Mussels, and Oysters. The most common symptoms include the following:

A.     Tingling & numbness of the lips, tongue, & throat

B.     Dizziness

C.     Vomiting

D.     Diarrhea

E.      Reversal of hot & cold sensations

PARALYTIC SHELLFISH POISONING is Saxitoxin in shellfish that are found in colder waters such as the Pacific and New England Coasts. Again, poisonous algae are the enemy that causes all of the problems. The shellfish involved here are: Clams, Mussels, Oysters, & Scallops. The symptoms are similar to Neurotoxin in the warmer waters, except that numbness may also occur. Death, due to paralysis, may result if high levels of the toxin are consumed.


There are three major types of fish poisons (toxins) that can cause a lot of human suffering, which are:

-- Scombroid Poisoning (histamine toxin)

-- Ciguatera Poisoning (ciguatoxin)

-- Mercury (toxic mercury)

SCOMBROID POISONING is also called histamine poisoning. Scombroid toxin is caused from time-temperature abuse, which is from human neglect in handling fresh fish. In other words, Scombroid type fish are left in the temperature danger zone (41 degrees F / 135 degrees F) for too long, which gives bacteria on the fish time to produce histamine (toxin). Once the toxin is produced on the fish; the histamine toxin cannot be destroyed by cooking, freezing, smoking or salting. There are certain fish that are commonly associated with scombroid poisoning, which are Bonito, Mahi mahi, Mackerel, & Tuna.

CIGUATERA FISH POISONING is caused by certain marine toxic algae in the Pacific Ocean, western Indian Ocean and the Caribbean Sea. Toxic algae can also be found in the Gulf of Mexico waters, as well as the cold northeast Atlantic Ocean. The toxic algae are also known as THE RED TIDE. Small fish in the oceans eat the toxic algae, and the larger fish eat the smaller fish. It is part of the ocean food chain. There is no evidence of the Ciguatera toxin in the fish that is poisonous since the toxin cannot be detected by taste or smell. When humans eat fish that have eaten the toxic algae, they become very ill, and the symptoms may last for months or several years depending upon the dose of the toxin eaten in the fish. Vomiting and nausea will always be the case in any type of fish toxin eaten, but tingling in the fingers, lips, or toes, or joint and muscle pain is also very common. The types of fish that are usually associated with Ciguatera toxin are Barracuda, Grouper, Jacks, and Snapper. When purchasing fish in the United States, it is very important to know where the source of the fish supply came from. In addition, the buyer needs to check to see if the supplier is an approved and reputable supplier. When purchasing fish from a catering company, know where the catering company purchases their fish supplies. When purchasing cooked fish from a white tablecloth restaurant in a foreign country, Buyer Beware! There may not be any guarantees that the fish were harvested from waters free of the toxic algae.

MERCURY FISH POISONING advisory was issued jointly by the FDA and U.S. Environmental Protection Agency in 2004, recommending that women of childbearing age, pregnant women, nursing women, and children not eat any shark, tilefish, king mackerel or swordfish. Albacore tuna, which is the most expensive white tuna, should have consumption limited to 6-ounces or less per week, and this includes canned Albacore tuna. Nearly all fish contain mercury, which is a toxin (poison). Both saltwater and freshwater fish have mercury contamination. The larger and longer-lived fish usually contain the most mercury toxins. In addition to the ocean fish mentioned above containing higher levels of mercury, there are also other higher risk species, with high concentrations of mercury, which are Largemouth, Hybrid, Striped, and White BASS fish, Pickerel, Gar, Catfish, and Sucker fish. There are a few lower risk species, which are Bream, Sunfish, Crappie, Pinfish, and Trout.

If you love fish and insist on eating it anyway, learn how to protect yourself to a small degree from mercury poisoning. Eat safer types of fish and avoid fish known to have high levels of contamination. Large amounts of the Mercury toxins are in the organs, skin and fat of the fish. Cook or order fish that has been grilled, so that the fat can drip away from the fish. Avoid deep fried fish because the skin is still on the fish. Mercury toxin in fish cannot be destroyed by cooking or freezing the fish. Remember, fresh or frozen fish sold in stores or cooked fish purchased in a restaurant or from a catering company are no exception to the mercury contamination danger.

Contaminated fish may not look, smell, or taste different, but the dangers and concerns about eating fish with high levels of mercury, which everyone should be aware of:

A.     Childhood attention & language deficits

B.     Memory loss

C.     Mental retardation

D.     Impaired vision

E.      Motor & nervous system functions

F.      Heart disease & heart attacks 

This article is not intended to frighten the reader, but to make everyone aware of the dangers of Mariscos el Veneno, (Poisonous Seafood). Caution is the message in this article about seafood. Seafood is probably the most high liability and dangerous type of food eaten and served throughout the world. As a certified food safety instructor, I would advise anyone in the General Aviation industry, who orders food for a flight, or eats seafood any place in the world, to always be mindful of the information in this article. 

Clarification of poisonous algae (called the Red Tide). Algae are not always poisonous throughout the year in any of the oceans in the world. It is not always known when the algae will become poisonous in any body of water. When ocean algae becomes poisonous, it tends to changes colors, which becomes a danger alert for the fishing industry. Algae can become dangerous several times per year, but usually for only a few weeks at a time. It is against the law to fish waters where there are Red Tide conditions, but there are always those who break the law. Eating fresh seafood in the United States is probably a lot safer than any other place in the world. Take time to inquire about the source of the seafood and then make your decision to eat seafood or likewise.


  • CDC: Center For Disease Control: Atlanta, GA

  • ServSafe Essentials Fourth Edition

  • Pittsburgh Post-Gazette, Don Hopey

  • DHR: GA Department of Human Resources

Author Information:


Jean Dible is president and founder of GA Food Safety Professionals, a mobile food & alcohol safety training school in Atlanta, GA. Jean is a contributing writer to the Corporate Flight Attendant Community website; her Your Food Safety Connection column appears here on a bi-monthly basis.