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From pufferfish and maggot cheese to rhubarb leaves and rotten fish, these dishes should come with a health warning
Fugu (pufferfish): Japan
Certainly not as repugnant as some of the other dishes on our not-to-be-tried-at-home menu, fugu – or pufferfish – has nevertheless become a notorious delicacy thanks to the fact that eating it can be fatal unless the dish is properly prepared. The fish's liver, ovaries and skin contains large amounts of the poison tetrodotoxin and there is no known antidote.
Rather than just eating frog legs, as the French are famed for, some African nations, particularly Namibia, prefer to eat the entirety of the bullfrog. By doing this they risk kidney failure and death as the frog's skin and organ contain harmful toxins. Young frogs yet to mate are the most lethal.
Echizen Kurage: Japan
Otherwise known as Nomura's Jellyfish, echizen kurage is one of the largest jellyfish in the world. Cooked properly, it is a Japanese delicacy, however, its toxic parts must be removed, and it must not be eaten raw. The country even has a vanilla and jellyfish flavour ice cream.
Many Westerners would find the practice of eating a freshly-killed octopus particularly hard to digest, especially when, after the octopus is cut up, still squirming, on a plate before the diner's eyes, its suckers remain active, presenting a sizeable choking risk. According to one diner's report, it can taste like "a party in your mouth". Around six people a year die as a result of choking on the tentacles. Watch a video, not for the faint-hearted, of the wriggling octopus dish here.
Blood clams: China
These shellfish contain a number of viruses and bacteria that can cause hepatitis A, E, typhoid and dysentery. They require boiling thoroughly before eating. In Shanghai in 1988, more than 300,000 people fell ill after eating blood clams and 31 people died. It is estimated that around 15 per cent of people who eat the clams become infected.
Casu Marzu: Italy
This is a Sardinian speciality that comes with a health warning. Most food that's crawling with maggots finds its way into the bin but the decomposition of this "rotten cheese" is positively encouraged. Pecorino Sardo is set aside so that cheese flies can lay eggs inside the rind which then hatch into crawling maggots. These feed on the cheese, aiding fermentation and producing a pungent smell. Officially banned in the EU, the maggots are eaten live with the cheese, assuming they haven't jumped away first – some can jump up to 15cm. They are also known to be able to bore through the diner's intestinal walls.
Rhubarb leaves: worldwide
Seemingly innocuous, the green leaves of a rhubarb plant contain oxalic acid, a toxin that forms harmful crystals in your kidney and can cause renal failure. Symptoms include difficulty breathing, burning in the mouth and throat, diarrhoea, red urine, vomiting, eye pain and seizures. Deaths are rare, but have been reported.
Pangium Edule: Asia
Grown in the mangrove swamps of South-east Asia, the pangium edule is a tall tree that produces a large poisonous fruit with seeds that contain hydrogen cyanide. However, the fruit is used in cooking in the region; proper preparation is essential, by boiling, then burying it in banana leaves and ash for 40 days.
Fesikh is the name of a fish dish eaten on the day of the Egyptian spring festival, Shem el-Nessim, made up of fermented (sometimes rotten), salted and dried grey mullet, prepared by being left in the sun before preservation. The preparation is an elaborate process, the responsibility for which passes down from father to son. However, each year, incorrect preparation leads to bouts of food poisoning - this year six people were hospitalised. Two people died from eating the fish in both 2009 and 2010, and in 1991, 18 people died.
Cassava: South America
Eaten boiled, fried, steamed, baked, grilled or mashed, the cassava plant, a root vegetable in South America, contains a high concentration of linamarin, which can produce cyanide if prepared incorrectly. In 2005, 27 children died and a hundred more fell ill after eating cassava as a snack at a school in the Philippines.
Hákarl (fermented shark): Iceland
An Icelandic speciality, hákarl is certainly an acquired taste. It is traditionally made by gutting a basking shark, placing it in a hole, covering the carcass with gravel and stones and then leaving it to ferment for up to three months. The shark is then cut into chunks which are hung for several months more. The smell is repugnant, although the taste is said to be reasonable. However, it can cause food poisoning if not given sufficient time to ferment fully.
Beware next time you are sampling nature's produce, eating an unripe elderberry, or the plant's leaves, twigs or seeds, risks cyanide poisoning, which can cause severe diarrhoea and seizures. Stick to the cordial.
The Telegraph, London