I have been experimenting with sprouts lately. Most recently I've been sprouting mung beans.

Last week I had a salad with a larger than usual portion of bean sprouts. I spent the next day with a delicious case of food poisoning. I don't have any proof that the sprouts were the cause but I have since read online that sprouts are prone to bacterial contamination and they were the only potentially risky thing I ate that day.

My process is simply:

  • Rinse the beans,
  • Place them in a mason jar with a mesh lid
  • Cover with water,
  • After one day drain the beans,
  • Twice a day, rinse them with fresh water and allow to drain,
  • Eat the sprouts after 3-7 days.

If bean sprouts do have an elevated risk of bacterial growth, how can I minimize that risk?

  • 2
    Sprouts may be the culprit, but not necessarily. Foodborne illness can take days or even weeks to manifest.
    – Jolenealaska
    Commented May 13, 2016 at 19:14

2 Answers 2


Some of my local supermarkets stopped selling sprouts because bacterial contamination was so widespread, but that's probably more of a problem for big batches. I'm thinking that the best things you can do at home to prevent unwanted bacterial growth might be:

  • Sanitize your jar before use. I think a hot water bath would work, or soak in a 10% bleach solution for 30 minutes (that's how I've sanitized in a lab).
  • Make sure to use beans that aren't old or of poor quality. This matters less when you're cooking them but is really important for sprouting.
  • Maybe try using a finer cover for the sprouts, like a layer or two of cheesecloth (I don't think this should matter too much though).
  • Use filtered water, not tap water to soak the beans.

I generally follow these rules when I'm sprouting and haven't had a problem.

As a relevant side note I believe the beans themselves contain their own endophytes, or native microbes that live inside, which is something to consider when sprouting. Not all bacteria/fungi are bad, and having more of the good ones there could prevent pesky pathogens (which reinforces my suggestion of using "good beans").

  • Following the last point it's worth noting that some beans seem to be more prone to this than others, mung beans seem a little more prone than most.
    – Niall
    Commented May 15, 2016 at 14:53
  • @Niall- That is interesting. Do you read that somewhere or is that an observation? Commented May 19, 2016 at 16:57

I am not sure why you need to store them in water. I have read that giving fruit and veggies a brief wash in a water and vinegar solution (say, 3 cups water to 1 cup vinegar) and then spinning them dry gently in a salad spinner, and storing in paper towels in a plastic bag helps keep those things fresh and mold-free longer -- perhaps it would work for sprouts, too?

  • Where does OP indicate storing in water? Soaking beans and other hard seeds before sprouting is standard procedure.
    – Stephie
    Commented May 14, 2016 at 6:49
  • It's just the way it is worded: OP says "soaking BEANS," not seeds, so it sounded to me like they were already through the sprouting process.
    – franko
    Commented May 15, 2016 at 21:37

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