Why You Should Think Twice Before Eating Pufferfish

Pufferfish can be served for human consumption as a delicacy called fugu. It is especially popular in Japan, but you may also see it available in other countries, including Korea, China, Singapore, and here in the US. However, there are risks associated with eating this dish because it can cause a deadly form of food poisoning. Here we will explain why pufferfish can be so deadly and why you should only eat pufferfish with extreme caution. You will also learn why it should only be prepared by qualified and experienced chefs.

Which Types of Pufferfish Can Poison You?

Pufferfish are called a variety of names, including globefish and blowfish. They belong to the Tetraodontiformes order, and there are hundreds of species. Their best-known feature is their ability to inflate their bodies when they are threatened – hence their name. Most are found in tropical and subtropical ocean waters.

In Japan, where most pufferfish are consumed, there are typically between 0 and 6 deaths per year, with 34 to 64 people hospitalized annually due to pufferfish poisoning. The types implicated in food poisoning incidents in Tokyo include the striped puffer (Takifugu xanthopterus), the vermiculated puffer (Takifugu snyderi), the genuine puffer (Takifugu porphyreus), the panther puffer (Takifugu pardalis), and the fine patterned puffer (Takifugu poecilonotus). The tiger pufferfish is both the most highly prized and the most poisonous of all pufferfish. However, all pufferfish from tropical waters should be considered poisonous.

You will find blowfish, also called northern puffers (Sphoeroides maculatus), in the waters of the Western Atlantic, from Newfoundland in Canada to northeastern Florida in the US. They are not reported to be toxic. However, the smooth puffer (Lagocephalus laevigatus) is also found in the Western Atlantic, including around New England, and it is poisonous. So, unless you are an expert at identifying pufferfish, it is sensible not to eat them.

The Dangers of Pufferfish

Pufferfish generally contain large amounts of a substance called tetrodotoxin (TTX) in their skin and viscera. It is a potent neurotoxin that is both tasteless and odorless, and it is not destroyed by cooking. When it is ingested by humans, it blocks sodium channels of nerve cells and muscles. The first stage of poisoning causes neuromuscular symptoms (such as tingling and numbness of lips, tongue, and throat), dizziness, headache, hypersalivation, diarrhea, and abdominal pain.

During the second stage, the initial symptoms get worse, and there is paralysis of the fingers and toes, and reflex changes. The third stage brings increased problems with swallowing, incoordination, and problems with breathing and the heart. In the final stage, there can be respiratory failure and seizures, leading to eventual death in some cases. The minimum lethal dose for humans is just 2 mg. Death can occur within minutes or hours, and there is no antidote.

Anyone experiencing the initial symptoms must seek medical attention immediately. Their chances of survival improve if they receive treatment to limit the body’s absorption of the toxin, relieve symptoms, and address life-threatening complications.

Where Does the Toxin Come From?

The fish are not born poisonous. They ingest TTX in the snails and worms that make up their diet and it is not excreted. Therefore, it builds up in their bodies and is concentrated in some organs, particularly the liver and ovaries, but also the skin and muscle in some species.

The snails obtained the TTX from plankton that they have eaten, and the plankton acquire it from marine bacteria that produce the toxin. It is possible to produce safe pufferfish by farming them and feeding them only TTX-free pellets. However, there are concerns that this practice could lead to complacency and increased confusion about which pufferfish are toxic.

Finding Pufferfish on the Menu

The country where you are most likely to find fugu on the menu is Japan. Most Japanese cities have at least one fugu restaurant. It is popular in the southern port cities of Korea and is available in China. However, the sale of all pufferfish (family Tetraodontidae), including fugu, is forbidden in the European Union.  

The importation of puffer fish products into the United States is restricted, and personal importation is prohibited by the FDA. There is limited availability, and only restaurants with special FDA approval can serve it. However, there have been incidents where illegally imported fugu has been consumed in the US and has resulted in people requiring hospital treatment.

The Northern Puffer is found from Cape Cod, Mass., to northeastern Florida, where they live over sandy bottoms near or amid seagrass in waters ranging from 3 to 180 feet deep. Unlike its tropical counterparts, it is not deadly poisonous according to the North Carolina Department of Environmental Quality. However, due to concerns that there could be low-level toxins in the skin and organs, fishermen are now advised to thoroughly clean the Northern puffer of all skin and viscera before eating. The overall message is that before you choose any pufferfish from a menu, make sure that you know which type of fish it is, where the fish has come from, and who has prepared it.

How Is Fugu Served?

Pufferfish flesh is white, and there are several ways of serving fugu. The most popular is sashimi, in which exceptionally thin-bladed knives are used to cut the fugu into translucent slices, which are then served raw in the shape of a rose. It can also be deep-fried, smoked, stewed, or the skin (with the spikes removed) can be eaten in salads. Pufferfish roe (eggs) are also eaten. In Korea, it is grilled, simmered, or eaten raw.

Despite being a prized and expensive delicacy, opinions vary on its taste. Some people argue that it is bland (especially when first tasted), while others describe the taste as “delicate,” with a firm and elastic texture. It can also be used to make fugu hirezake, a style of sake in which the fin of the fish is deep-fried and placed in hot sake.

Safe Preparation of Pufferfish

Only qualified, experienced, and licensed chefs can prepare pufferfish safely, and it should never be prepared by members of the public at home. Most fugu in Japan comes from Shimonoseki, located in Yamaguchi Prefecture in the Chugoku region of western Japan. In Tokyo, chefs need to take a written test and then a practical test to demonstrate that they can safely identify the edible and inedible parts of the fish and remove the poisonous ones.

The body parts that contain the toxins vary with pufferfish species. Therefore, the chefs must be experts at pufferfish identification before they can safely prepare them for human consumption. This must always be left to the professionals, and you should never attempt to do this yourself. Using very fine and sharp knives, they first remove the skin (pufferfish have no scales) by cutting around the mouth and pulling the skin off. Any jelly is washed off using salt, and the eyes are removed. The fish is then gutted, taking great care not to puncture the ovaries or the liver, where high concentrations of TTX are found. If these organs are punctured, the fish cannot be eaten. Then, the flesh is cut against the bone into very thin slices. Finally, the head is cut into two or three pieces, which can be boiled to make a stew.

What If You See Fugu on the Menu?

You are most likely to see fugu on the menu when traveling to countries like Japan. Cases of TTX poisoning from licensed restaurants are rare. Most cases arise from people attempting to prepare the fish at home. That said, it is important to make sure that the fugu has been prepared by someone who is licensed to do so and has received the necessary training. If you are in any doubt, it is best avoided. Finally, if you experience any symptoms after eating fugu, you must seek medical attention right away.