Food/ Vegetarian

Avoid Toxicity in Kidney Beans

Did you ever think you’d have to search out an article on how to avoid toxicity in kidney beans? Me neither, until I did.

I’m not writing this to be a fear-monger and I’m certainly not writing this to be a self-proclaimed food scientist (I’d fail miserably), but I learned something a little disconcerting about dry red kidney beans earlier this week. Because this wasn’t just news to me, but to many others as well, I decided to write a little tidbit in hopes to spread the word.

In fact, out of everyone I mentioned this to, only one person had been aware of it. ONE.

If you’ve ever worked with dry beans before, you know the drill; rinse, remove any small stones or debris that might have been missed, do a long or short soak, cook and eat. It all seems pretty straightforward, right?

beans

However, there’s a really important grey area (for lack of a better term) — one that I, and many others, had zero knowledge about.

Having only worked with dry lentils before, as far as I knew (and based on the cooking directions I’d read on the packaging which was the same for lentils, black beans and kidney beans alike), all I had to do was an overnight soak and then cook the beans the next day. When reading the word “cook”, I didn’t realize they meant “boil the red kidney beans for X amount of time to rid of *toxins* so you don’t shit your pants and end up in the ER”. (Toxins?) I figured cooking them in the slow cooker with the rest of my chili would be sufficient.

NOPE.

In fact, cooking red kidney beans at a lower temperature, such as 80 degrees C, can increase toxicity in kidney beans five-fold making undercooked kidney beans more dangerous than raw kidney beans.

Awesome.

The only reason I now know all of this is because after three hours of taking in the delicious aroma of my pumpkin chili on Monday, I had to dive in for a taste test; I couldn’t resist. Because the beans were still slightly crispy, I was curious as to how long they would take to become tender and cooked through. I went to Mr. Google, because Google is usually safe for cooking advice (unlike medical advice, yo), and that’s when I learned the awful truth about red kidney beans + Red Kidney Bean Poisoning (Phaseolus vulgaris) or Kinkoti Bean Poisoning.

I could feel the color drain from my face right then and there and my anxiety shot through the roof. I mean, I’d just done a taste test, so I’d be lying if I said that I didn’t nearly crap my pants right there in fear. Instead, I dragged my ass back down to the kitchen and discarded the chili with a huge frown on my face.

What is Red Kidney Bean Poisoning?

Raw kidney beans contain very high amounts of phytohemagglutinin, which makes them much more toxic than other types of beans. As I mentioned earlier, every package of beans I’ve seen has the same basic instructions on the back for quick soaks, overnight soaks, boiling, etc. NONE of them mention the absolute importance of boiling kidney beans at a high temp to kill toxins to dodge poisoning — a poisoning that could result in hospitalization. Even after an overnight soak, which many claim to be unnecessary anymore, kidney beans need to be boiled for at least 10 minutes to kill toxins. (Though, in the Bad Bug Book, the US FDA recommends boiling them for 30 minutes to completely destroy the toxin.)

There is no room for slow cooker action here; if you’re like me, and figured the slow cooker would do the cooking, think again. As I mentioned above, undercooked beans can be more toxic than raw beans.

What happens if you consume raw or undercooked kidney beans?

  • Mortality: not reported.
  • Toxic dose: As few as four or five raw beans can trigger symptoms.
  • Onset: Usually begins with extreme nausea and vomiting within 1 to 3 hours of ingestion of the product, with diarrhea developing later within that timeframe.
  • Illness + complications: Upper and lower gastrointestinal illness. Vomiting may become severe.
  • Symptoms: In addition to vomiting and diarrhea, abdominal pain has been reported by some people.

So yeah. That’s a thing.

I wanted to write this dojigger so I can reference to it in the future when posting recipes that include red kidney beans and, most importantly, to spread awareness. It’s obviously a little *too* easy to make this mistake.

The good news is I didn’t get sick; the best news is that I made my Pumpkin Chili With Pumpkin Beer again yesterday and it’s basically the best chili ever. (Recipe coming soon!)

References:

The Bad Bug Book | Center for Food Safety and Applied Nutrition (CFSAN) of the Food and Drug Administration (FDA), U.S. Department of Health and Human Services

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26 Comments

  • Reply
    Liane Linner
    November 25, 2018 at 4:51 pm My slow-cooker is boiling the red kidney beans. So... thank you for posting this article! The slow-cooker is on high. Yes, I soaked the beans overnight and rinsed them before putting them in the slow-cooker with new water. This is going to be ok, right?!!
    • Reply
      Killing Thyme
      November 25, 2018 at 6:56 pm Hi Liane, Even after an overnight soak, it's highly suggested to boil the kidney beans in a rolling boil for at least 10 minutes to kill toxins. (Though, in the Bad Bug Book, the US FDA recommends boiling them for 30 minutes to completely destroy the toxin. So use your best judgement.) You said that your beans are boiling in your slow cooker? I've never been able to get a rolling boil in a slow cooker before, but if you have a model that gets that hot and your beans are surely boiling, you should be good. I'd just discard of that water once done before adding anything else to the slow cooker if you're adding anything else to the beans. Good luck!
  • Reply
    Joy H
    October 30, 2018 at 8:51 am I am a dietitian and I did not know this about uncooked dry beans until yesterday - when it happened to me. I had bought some beautiful dried beans from a local producer. They are NOT kidney beans, but a different variety called "flambo." I soaked them until tender before putting them to slow cook with a smoked ham hock. But after the soak, I snacked on a few beans (I'm talking 5-10, so not a lot) before they were cooked (my slow cooker on low actually brings to a boil, so I was not worried about the slow cook). Hours later I was violently ill, throwing up and explosive diarrhea. Nobody else in my house was ill, and it was so obviously a toxic-type reaction that I got online and did some research. Although the compound is noted to be very high in kidney beans, I wonder if it is in other heirloom varieties as well, but just has not been tested in every variety? Anyhow, bottom line for me is that I will not be snacking on soaked, uncooked beans EVER again. But I love beans and they are so good for me that I plan to continue eating lots of them!
    • Reply
      Killing Thyme
      October 30, 2018 at 10:03 am Joy—I am so sorry that you ended up sick! I hope you're feeling better. This article has been trending quite a bit lately from what my stats are telling me. So hopefully the word is getting out there. I was completely shocked when I first learned about this too, not to mention surprised at how little information is out there. I had to dig. I'm with you, I love beans! I won't give them up. Just have to make sure they are cooked. Hope you're doing ok!
  • Reply
    Scissorhands
    June 9, 2018 at 3:20 am Painful stomach as I read this. Lately I have been having a pain in my colon I think too. I thought it was the high leek, onion, garlic foods I've been eating, but now realise its the red kidney beans that I have been eating for the last few weeks. Oh well, at least I know now, and hopefully it has not shortened my life. Can you do the boil them thing after a long simmer?? Gonna stick with black turtle beans in the future
  • Reply
    Crispy Baked Falafel With Spinach | Killing Thyme
    April 9, 2018 at 4:03 pm […] Some recipes out there do call for canned chickpeas and the “saving grace” is the use of flour to act as a binding agent, because grinding up cooked chickpeas and frying them will have them falling apart otherwise. But cooked chickpeas + flour = dense and starchy balls. So, your best bet is to give dried chickpeas a good soak overnight and grind them with your other ingredients while they’re raw. (It’s ok, they aren’t dangerous like raw kidney beans.) […]
  • Reply
    Eleanor
    May 16, 2017 at 4:48 pm I simmered the beans in a crockpot for 5 hours then read this article if I boil beans now will that kill the toxin???
    • Reply
      Killing Thyme
      May 17, 2017 at 9:50 am Hi Eleanor, Sorry for the delay in response. How did things go?
  • Reply
    Dylan Cutler
    September 14, 2016 at 1:08 pm Sooo being a vegan I eat beans A LOT and I avoid all things canned (BPAs), so I need details here! When you say boil for 10-30 minutes, is this the beans being AT a boil for that long? OR a slow simmer maybe? Oh the stress of a simplistic task!
    • Reply
      Killing Thyme
      September 14, 2016 at 8:40 pm Hey Dylan, Based on my research, it's suggested that kidney beans be soaked in water for at least 5 hours, then drained, and boiled in fresh water for at least 30 minutes. Some people claim they boil them for 10 minutes and it's sufficient. I think 30 is probably a bit much. I always end up cooking lentils for much less time than the instructions suggest. See how they are after 10 minutes and go from there, I'd say. The point is to cook them through at a high temp to kill the toxin --- but you obviously don't want to end up with a pile of mush, either.
  • Reply
    Bernice
    September 12, 2016 at 2:39 pm wow. We eat a lot of beans and I have NEVER heard of this. I am definitely sending this to my daughter, who is vegan and soaks her own beans. Just wondering though, could you have dumped your chili into a pressure cooker and saved it?
    • Reply
      Killing Thyme
      September 13, 2016 at 10:36 am Hey Bernice, I'm not too familiar with pressure cookers, so I'm not sure. (I'm one of those people who isn't really comfortable around them, though I'm sure they've come a long way, I can't get past my fears of them blowing up, haha). From what I gather, the beans need to cook quickly and thoroughly at a high heat, which just won't happen in an oven or slow cooker. I would think that putting the entire chili in a pressure cooker *could* help the beans, but would it turn everything else to mush?
  • Reply
    Cassie | Crumb Kitchen
    September 11, 2016 at 7:43 am I saw your post when you first learned about this...AND I WAS TERRIFIED TOO. Being someone who likes to save money for recipes, I always buy my beans in large dry bulk bags. I had NO IDEA this was a thing, but thank you so much for spreading the word! (Time to go throw out my freezer meals now, boo.)
    • Reply
      Killing Thyme
      September 13, 2016 at 10:32 am Oh no! Such a bummer that you have to pitch food, too. I mean hey, at least we know now, right? I'm glad I wrote this in a timely manner.
  • Reply
    Elaine @ Flavour and Savour
    September 9, 2016 at 7:12 pm Who knew?? I read this earlier in the week and was surprised. Your post is super-informative and will be one we could link to in our own future recipes using kidney beans. Thanks for doing all the hard work for the rest of us :)
    • Reply
      Killing Thyme
      September 13, 2016 at 10:31 am I'm glad you found this informative, Elaine! I'm not great with science-speak, but I knew I had to put the info up somewhere. I'd be more than happy to have people use this as a resource when posting bean recipes. Haha, doing the hard work was my pleasure if it means happy bellies and safe chilis :)
  • Reply
    Vicky Chin
    September 9, 2016 at 6:42 pm Thank you for the info! I didn't know anything about it. The symptoms sound aweful! Sorry you have to discard the chili, but glad you didn't find out the hard way!
    • Reply
      Killing Thyme
      September 13, 2016 at 10:30 am Thanks, Vicky! I'm really glad I didn't find out the hard way, either. Haha. My goodness.
  • Reply
    Sean
    September 9, 2016 at 5:24 pm Before I started Diversivore, I was complaining to my wife about the fact that this is never pointed out on packaging, or in cookbooks. I've even seen cookbooks that include dry, unboiled kidney beans in recipes, and it drives me insane. I wish I'd thought to write it up - but now I'm VERY glad that you did! My condolences to your chili, which was undoubtedly AMAZING (albeit poisonous). Can't wait to see the final, safe version!
    • Reply
      Killing Thyme
      September 13, 2016 at 10:28 am It really blows my mind that this isn't on packaging. The fact that the cooking instructions are *exactly* the same as the less/non-threatening beans is ridiculous. I mean, put SOMETHING on there for crying out loud. I'm not posting bean recipes without linking back to this from now on. The good news: the final and safe version was a TOTAL win. Can't wait for lunch today :)
  • Reply
    Cristina @ I Say Nomato
    September 9, 2016 at 2:13 pm Oh no! That poor chilli! I'm so glad you caught yourself in time. That's so scary. And you're so right, definitely not something people know about. Also, all those 'make your own infused olive oil' things on Pinterest? Breeding grounds for botulism. So scary! Thanks for sharing this!
    • Reply
      Killing Thyme
      September 13, 2016 at 10:26 am Honestly; I get so upset over food going to waste even if it's a bit of leftovers, let alone an entire batch of it. I didn't know that about the infused olive oil! That used to interest me so much, but to hell with that. Some DIY stuff just shouldn't be DIY, haha.
  • Reply
    Diane Galambos
    September 9, 2016 at 12:25 pm I just read this even before you posted to Blog Share Friday! I join the ranks of those who did not know this. I only began using beans from scratch this year - so far, mainly chick peas. Makes one feel you dodged a bullet. So many hidden evil things. Family member just recovering from pressed juice food poisoning :-((( Thx Mardi! Diane (FBC-er_
    • Reply
      Killing Thyme
      September 13, 2016 at 10:24 am Hey Diane, that's awful to hear about your family member. I hope they're feeling better now! You're right, it seems as though there are so many little evils that we should know more about. I definitely feel like I dodged a bullet, haha. I usually have an iron stomach, but I have a feeling you can't hide from this one since consuming even as little as five beans can be detrimental :|
  • Reply
    Barbara Nee
    September 8, 2016 at 11:38 pm Thanks for writing this! I did not know about this, and now that I'm using my slow cooker more, this is very good to know.
    • Reply
      Killing Thyme
      September 13, 2016 at 10:21 am I'm glad you found the info useful, Barbara! It's crazy to me how this sort of thing isn't well known.

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