How to Avoid Food Poisoning from Undercooked Beans

Co-authored by Nimisha Gandhi

Last Updated: June 5, 2024 Approved

Undercooked beans may seem fairly innocent, if a little gross. However, they can cause food poisoning if you're not careful to cook them properly. The problem is caused by a plant lectin, phytohaemagglutinin or hemagglutinin. If the beans are not cooked properly, it can cause a broad range of digestive problems with a variety of symptoms.

Part 1

Part 1 of 2:

Cooking Beans Properly

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After the beans have been soaking, it's a good idea to boil them to remove any remaining hemagglutinin. Bring the beans to a boil, and let them boil for 10 minutes before cooking as you normally would.^{[1]
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Cook your beans thoroughly. The best way to avoid food poisoning from beans is to ensure they are cooked thoroughly. Each type of bean takes a different amount of time to cook, so read the back of the package, or find a chart on the web for the style of cooking you plan to use. You can choose to boil them, cook them in a pressure cooker, or use a slow-cooker. Beans should be soft and tender when they're done.
- Several beans need only a relatively short cooking time: red lentils (cook 20-30 minutes, pressure cook 5-7 minutes), black (turtle) beans (boil for 45-60 minutes, pressure cook 15-20 minutes), fava or broad beans (cook for 45-60 minutes, don't pressure cook), and great northern (cook 45- 60 minutes, pressure cook 4-5 minutes).
- Some need a bit longer: chickpeas (cook 1.5 to 2.5 hours, pressure cook 15-20 minutes), kidney beans (cook 1 to 1.5 hours, pressure cook for 10 minutes), lima beans (cook 60-90 minutes, don't use pressure cooker), and pinto beans (cook 1.5 hours, pressure cook 10 minutes).
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Beans produce foam at the top of the pot when you boil them. This foam is harmless, however, and it will be reabsorbed by the broth. However, you can skim it off if you'd like.
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Soak the beans overnight. Soaking the beans helps remove the harmful plant lectin, hemagglutinin. Cover them in clean water with an inch or two extra at the top. Place a lid over them. Leave them to soak overnight.^{[2]
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- Discard the water before cooking.

Part 2

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Staying Safe

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If you're really worried about food poisoning, canned beans are a safer option than dried beans. They are already thoroughly cooked in the can, so you don't have to worry about cooking them.
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Choose beans that are lower risk. Red kidney beans have the highest concentrations of hemagglutinin, so they put you the most at risk. If you're worried, pick a bean with a lower concentration, such as cannellini beans or broad beans.^{[3]
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- Chickpeas also contain much less hemagglutinin than red kidney beans, and lentils have an even smaller amount.
If you do eat undercooked beans, look for symptoms of food poisoning. You may have nausea, vomiting, and diarrhea. You may also have cramps or abdominal pain. Generally, these symptoms appear within 3 hours of eating the beans. Visit urgent care or the ER if your symptoms are severe.^{[4]
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