Some of our local foods are actually poisonous | campus.sg

poison food ingredient

We all know that some foods, like pufferfish, are poisonous, but sometimes we tend to forget that some of our local foods are also pretty dangerous to eat. Here are some local ingredients that are also toxic if not prepared properly or are served in excessive quantities:

Nutmeg

via Pixabay

Whether you’re aware of how much nutmeg goes into your food, knowing that two teaspoons of the spice is enough to cause convulsions (according to AsapSCIENCE), will make you think twice. Nutmeg has been used historically as a drug – snorted, smoked, eaten in large quantities – to produce a high, with side effects like nausea and dizziness. According to research by the International Programme on Chemical Safety, 1 to 3 nutmegs, or 5 to 15g (1 to 3 teaspoons), is the reported toxic dose but this intoxication usually passes in 24 hours.

Buah Keluak

Curry with buah keluak (via Wikipedia)

The kepayang “fruit”, or buah keluak, is the nut of a native tree which is often used in Peranakan dishes, such as asam buah keluak. The raw seed contains cyanide, which when ingested can cause general weakness, dizziness, and coma; if ingested in high amounts, it can kill. The seeds have to go through a painstaking process to make it safe for consumption. Traditionally, the seeds would be boiled, soaked, and then buried in ash wrapped in banana leaves for as long as 40 days. Even after all that treatment, some people continue the alternate soaking, scrubbing, and rinsing for days – even weeks – to ensure that the water-soluble cyanide is completely gone.

Cashews

via Pixabay

Cashews are technically not nuts, because its seed actually grows outside the fruit (called cashew apple). They’re also not supposed to be eaten raw because they contain anacardic acids, a black-coloured resin that’s toxic if ingested (it’s related to poison ivy), and can cause rashes, blisters, and burns if it contacts the skin. Cashews have to go through a roasting or steaming process to make them safe to eat, which is why you’ll never see them sold with their shells (like peanuts). While we may not have to worry about the resin, the production of cashew nuts – concentrated in Vietnam, India, and Ivory Coast – shows a worrying trend of using forced or low-wage labour to cater to the growing demand for the nut.

Starfruit

via Pixabay

While starfruit is not technically poisonous to most people, it can have a toxic effect for those who have kidney disease because the neurotoxin in the fruit can enter the brain and cause neurological disorders. There have been documented cases where ingestion of the fruit led to poisoning of dialysis patients and people with kidney disease. Symptoms include hiccups, vomiting, weakness, mental confusion, and psychomotor agitation, and in extreme cases, coma and death. However, healthy people can clear out the toxin through their kidneys without problems.

Cassava (source of tapioca)

via Pixabay

You may not be familiar with cassava, but you’ll definitely know one of its products: tapioca, aka the “bubble” in your bubble tea. Tapioca is made from cassava starch. While cassava itself is an edible root consumed by people around the world, it actually contains cyanide and can be deadly if not prepared properly by soaking, drying, and scraping before being consumed. Luckily tapioca flour won’t kill you (what a relief!) as it’s been processed multiple times, but avoid eating cassava unless you know it’s been processed completely.

Red Kidney Beans

via Pixabay

Kidney beans are safe to eat when properly cooked, but if they’re raw or partially cooked, they can cause gastrointestinal upset due to the naturally occurring toxin called phytohaemagglutinin. Due to its high concentration of the toxin, just eating four or five raw or even slightly undercooked beans can trigger the symptoms, which include nausea, vomiting, stomachache, and diarrhea which occur within a few hours of consumption. A study found that if you soak the beans overnight to soften them, and then boil them at a high temperature for at least 10 minutes, the toxin drops to a safe level.

Rhubarb

Rhubarb pie (via Pixabay)

Rhubarb isn’t something that we’re used to in the tropics and some of us may only know rhubarb as an ingredient in tarts (and other sweet treats). In its raw form, it looks like a red/magenta-coloured celery. While it looks pretty, its leaves are spectacularly poisonous because they’re very high in oxalic acid. According to National Geographic, oxalic acid binds to calcium ions in your blood and makes them ineffective, leading to kidney failure or even death. About 25g of pure oxalic acid can kill a human, which translates to about 11lbs of the leaves – which nobody eats anyway.