Highly poisonous blue-ringed octopus found in hotpot restaurant! What other seafood should we pay attention to?

Recently, the blue-ringed octopus has become a hot topic: A friend was eating at a hot pot restaurant and found that one of the octopuses he ordered looked different from the others, so he took a photo and posted it on Weibo. As a result, he got a reply from @博物: It was a blue-ringed octopus, which contains tetrodotoxin, which is extremely toxic and does not decompose when heated .

The blue-ringed octopus is extremely toxic and does not decompose when heated. Sina Weibo: @博物杂志

What exactly is a blue-ringed octopus? How can we tell when a highly toxic octopus is mixed into food? What other potentially dangerous ingredients might we encounter when we eat seafood?

Deadly blue-ringed octopus

The blue-ringed octopus is not a separate species, but a common name for species in the genus Hapalochlaena . There are currently four known species: the striped octopus (H. fasciata), the crescent octopus (H. lunulata), the spotted octopus (H. maculosa) and the Nierstraszi octopus (H. nierstraszi). Among them, the striped octopus and the crescent octopus are distributed in tropical and subtropical waters of China.

4 types of octopus:

Crescent Leopard Octopus | Rickard Zerpe / Wikimedia Commons

Striped leopard octopus | Totti / Wikimedia Commons

Spotted leopard octopus | Sylke Rohrlach / Wikimedia Commons

Leopard octopus | reeflex.net

The blue-ringed octopus that has become a hot topic may be a crescent leopard octopus. The biggest feature of the blue-ringed octopus is that its body is covered with blue rings or stripes, which are very conspicuous when alive. However, not all octopuses with rings are poisonous. For example, the common edible octopus, Octopus brevis, has a pair of golden rings on its body, which is an important feature of it.

Octopus | zukan-bouz.com

Fresh octopus in the market also has a golden circle under its eyes｜zukan-bouz.com

In fact, many cephalopod species such as octopuses and squids have toxins, which allow them to quickly paralyze their prey when hunting. Fortunately, most of these animals have very weak toxicity, which is only effective against crustaceans such as shrimps and crabs, and is almost harmless to humans.

However, the main toxin in the blue-ringed octopus is tetrodotoxin , which is one of the most toxic non-protein natural toxins in nature , 100 to 1,000 times more toxic than sodium cyanide. The blue-ringed octopus produces toxins through several bacteria that live in the body. The toxins are mainly distributed in the saliva, and some toxins are also found in the mantle and ink. The toxins are an important tool for the blue-ringed octopus when hunting and defending itself. After attacking the prey, they will inject the toxins into the prey's body, causing the prey to quickly lose consciousness.

Blue-ringed octopus predation｜Eunjae Im - Underwater Imaging Productions

Ordinary cooking cannot decompose tetrodotoxin , so eating blue-ringed octopus can also cause poisoning. There have been several records of casualties caused by eating blue-ringed octopus poisoning abroad, and there was also related news in China in 2014: In Taiwan, someone accidentally ate blue-ringed octopus and experienced nausea, vomiting, dizziness, weakness, numbness and other symptoms shortly after eating. Fortunately, he was sent to the hospital in time and barely saved his life after rescue.

Don't try it out of curiosity.

The blue-ringed octopus that has become a hot topic this time has made many people feel concerned about seafood and other ingredients. For marine creatures, they have to survive in the vast and dangerous ocean, and it would be difficult to survive without some poisonous skills. For diners, avoiding potentially dangerous ingredients can greatly improve the safety index.

Toxic marine organisms that may be mixed into food can be roughly divided into the following categories:

Toxins in the body

Blue-ringed octopus is one of these, and if eaten by mistake, it may cause poisoning. The characteristics of blue-ringed octopus are relatively obvious and easy to identify. If you prepare the food yourself, you can tell it apart with a little more care.

Obviously different from other octopuses｜Sina Weibo: @y1xuan

Some organs are toxic

The most famous of these is pufferfish . As one of the three delicacies of the Yangtze River, pufferfish's ovaries, liver and other organs are poisonous, and the toxin is tetrodotoxin, but because the meat is delicious, many people are still willing to take the risk to taste it. Fortunately, if the pufferfish is handled by an experienced chef, it will generally not cause poisoning to diners, and now artificially cultivated pufferfish can also be eaten safely .

Common spotted pufferfish Sphoeroides maculatus | Wikimedia Commons

The bile of some Cypriniformes fish contains sodium cyprinid sulfate, which is also toxic. Once it enters the human body, it will damage the renal tubules, leading to acute renal failure and even death in severe cases. Moreover, this substance will still be toxic after being heated or soaked in wine.

Among common edible fish, crucian carp has the most toxic bile｜George Chernilevsky / Wikimedia Commons

Eating food that accumulates toxins

Some creatures cannot produce toxins themselves, but they eat foods rich in toxins , which leads to the accumulation of toxins in their bodies. For example, the toxins in the bodies of many crabs such as the upright clean crab, the patterned clean crab, and the copper-cast cooked crab are mainly pufferfish toxins and saxitoxins. Some people once sold upright clean crabs as "brown crabs", and diners were poisoned after eating them.

Bronze cast of cooked crab | Sébastien Vasquez / Wikimedia Commons

Some benthic organisms, such as shellfish and crustaceans, especially filter-feeding organisms, are prone to accumulating toxins due to water pollution . Factors such as red tides and wastewater can cause a large amount of toxic substances to accumulate in the bodies of these animals, and humans may also be poisoned after eating them.

During the peak red tide season in April and May every year, news of poisoning from eating mussels occurs from time to time｜Pixabay

The stinger or venom gland is toxic

Some creatures have evolved organs such as stingers for self-defense. For example, the rose scorpionfish, brown basketfish, lionfish and some sea urchins all have specialized spike-like organs; some species also have venom glands that can inject venom when piercing the body. If these venoms are injected into the human body, they will cause redness, swelling, pain, and in severe cases, disability or even death. If the stingers are removed, these ingredients can be eaten safely.

The common lionfish in the animal world is also poisonous | Jens Petersen / wikimedia Commons

Toxins produced by spoilage

After many seafood die, the bacteria in their bodies will multiply in large numbers, and the flesh and internal organs will deteriorate in a very short time , while producing toxins. Eating such seafood may cause food poisoning, so seafood must be eaten fresh .

Many seafood and river food have this problem, such as the Chinese mitten crab, also known as the "hairy crab", which should be eaten fresh | Tuchong Creative

Pathogens or parasites

This situation is more serious in freshwater and brackish water organisms. The hepatitis A epidemic in Shanghai in 1988 was caused by people eating clams contaminated with pathogenic bacteria. In some areas, people are accustomed to eating raw fish, raw drunken shrimp, raw drunken crab, etc., which are also very easy to be infected with parasites such as liver flukes. For this kind of situation, just avoid eating raw food and cook seafood thoroughly to avoid it.

There is no heating step in the production process of raw drunken shrimp. Alcohol marination alone cannot completely kill liver flukes | James Creegan / wikimedia

In general, buying food from regular vendors and cooking the ingredients thoroughly can avoid most food poisoning. If you encounter strange ingredients, you can be more careful. Knowing more about species can sometimes really save your life.

However, there are so many creatures in the sea that it is difficult for us to recognize them all. Therefore, whether you are eating seafood, diving, or walking on the beach, you must pay more attention when you see unfamiliar creatures. Don't touch them out of curiosity, and don't try them out of greed . Maybe an inconspicuous little guy can make you unforgettable for a lifetime.

Beautiful Portuguese man-of-war, don't hesitate to take a picture of it when you see it on the beach! ｜4Neus / flickr

Author: Erzhu

Editor: Mai Mai

This article comes from the Species Calendar, welcome to forward

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