Octopus can be eaten raw, but would you eat it if it still wriggling? Sannakji is a Korean dish of baby octopus which is cut into pieces while still alive and served immediately, or sometimes wrapped around chopsticks and eaten whole. It poses a choking hazard because the suction cups are still active and can cling to your throat. Approximately six people die every year eating this deadly dish.

Infamous for being both a Japanese delicacy and potentially lethal, fugu, also known as pufferfish, can only be prepared by specially trained chefs. The internal organs of the pufferfish contain a deadly poison, tetrodotoxin, which is 1,200 times stronger than cyanide and can paralyse the body’s muscles – every few years a death is recorded.

You’ve probably heard of Jamaica’s national dish, ackee and saltfish, which features pieces of the fruit cooked with salted codfish. But do you know about the dangers associated with unripe ackee? The unripened fruit and seeds contain the toxins hypoglycin A and B, so must never be harvested prematurely. Consumption causes vomiting, which can be severe enough to cause death.

With a name as ominous as blood clams, you might expect there to be danger involved. However, the molluscs’ red colour, caused by high levels of haemoglobin (the protein that makes blood red), is not what makes them risky. It's because they're often eaten raw and have a track record of spreading diseases including hepatitis A, typhoid and dysentery. They must be boiled for long enough to kill any bacteria.

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If you love to snack on cashew nuts, you may be surprised to see them on this list. But in their raw, unprocessed state, cashews contain urushiol which is a chemical also found in poison ivy. It causes skin rashes and can be lethal if ingested in high doses. It's a good job the type you find in the supermarket are cooked at a high heat at least once before sale. Cashews might still be labelled as raw if they haven't been flavoured or roasted further, but they will have been treated and are safe to eat.

Every year health warnings are issued against eating fesikh, a fermented and salted fish dish traditionally eaten during the Egyptian spring festival Sham el-Nessim. If fesikh isn't prepared with enough salt or undried fish is used, it might be left in anaerobic conditions for weeks with the perfect environment for dangerous, botulism-causing bacteria to grow. In 2019, 70 people were hospitalised including one fatality in the Egyptian city of Alexandria alone.

Have you ever wondered why we eat the sour stalks of rhubarb plants but not the leaves? The reason is the leaves contain high levels of oxalic acid. Spinach, chard and cocoa contain the compound too. In large doses it binds with calcium in the body forming crystals which can grow into painful kidney stones. In really large doses it depletes calcium levels so much it can cause death.

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Just one species of frog that’s eaten around the world, the African bullfrog is a delicacy in parts of Namibia and Zambia. The animals grow to huge sizes and are prepared whole – not just the legs are eaten like in France. However, they can be poisonous and cause kidney failure if they’re not harvested at the right time of year or prepared correctly.

Used to make tapioca, fries, cake and bread, the root crop cassava is a great source of carbohydrate. However, when raw it contains the poison cyanide, so must be cooked in one of a number of ways: by boiling, grilling or steaming, for instance. If cassava is not prepared correctly, it can be particularly dangerous for children to eat.

Found in the jungle in Malaysia, Indonesia and Singapore, pangium edule is a tall tree which bears huge rugby ball-shaped fruit. While its fleshy insides can be pickled or cooked to eat, great care must be taken while preparing the fruit. The skin is full of the poison cyanide, so they must be soaked in running water for days, then boiled and peeled.

Chewing on a cherry, apricot or peach stone or the pips from an apple should be avoided, because they contain a compound that turns into cyanide in the body. The doses are small, so unless you consume a lot, the effects are unlikely to be fatal. This is not the same as accidentally swallowing a whole stone – when you do this it usually passes through your system intact. 

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Jellyfish are more famous for their nasty sting but it's also eaten around the world. However, it must be a species that's edible for humans and it must be prepared correctly. The mauve stinger, found in the Mediterranean, is one such edible species. It's cooked in lemon juice, vinegar and water, which gets rid of the dangerous chemicals. Then it's typically battered and fried. Meanwhile, boiled jellyfish salad is a popular Chinese dish.

Most of us love a slice of cheese, but creamy casu marzu is created by leaving pecorino (a hard cheese similar to Parmesan) out for cheese flies, which lay their eggs inside the rind. Maggots hatch and feed on the cheese which softens it and gives it its unique flavour. They’re not removed before you eat the cheese and some experts warn there's a risk of maggots causing damage to your intestine. So make sure you chew properly.

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Purple-black berries that grow on elder trees in Europe and America, elderberries have historically been used to treat winter colds and flu. If you find yourself wanting to have a go at making elderberry cordial or wine, it’s imperative you cook the fruit properly. The raw berries, bark and leaves contain the poison cyanide.

It has a bad reputation for having hallucinogenic properties and was banned in many European countries and the US for most of the last century. However, the botanical spirit absinthe, once accused of containing psychoactive chemicals, doesn’t have nearly enough to cause a negative effect. What’s really the most dangerous thing about it is its alcohol content which can be as high as 74% ABV (148 proof).

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A traditional Icelandic food, hákarl is Greenland shark that has been fermented for six months. If eaten fresh, it would be poisonous because the sharks have high levels of toxins in their flesh. It’s considered safe to eat after it has been given time to age and neutralise – but it retains a strong concentration of ammonia which can be very off-putting.

Becoming more common in supermarkets in the US and UK, starfruit is a bittersweet fruit with a distinct five-point shape, native to Asia. Most people have no trouble eating it, but it must be avoided by those with kidney problems. It contains a toxin, which if not broken down by the kidneys, causes neurological conditions.

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