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May 19, 2006 05:00 AM

Does Natto (fermented soy beans) spoil?

  • t

Was wondering if Natto spoils. mine has been in the fridge for 2 months almost and it still looks and tastes fine and I feel fine so I'm guessing the answer is that it doesn't. (I was craving it and had to eat some.) There's no expiration date on the packaging just a very long distance phone number. my japanese isn't that great so I was wondering if anyone out there knew. thanks in advance - tom S.

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  1. I have never used natto, but considering that my bf uses fermented soybeans as bait when fishing for catfish, (and it smells worse than stinkbait) I would say it *could* spoil!! :-)

    1 Reply
    1. re: Katie Nell

      But that's how it smells when you eat it at a restaurant...sort of an aquired taste one might say. So, I don't know if that's an indicator.

    2. Don't know about natto, but I've had fermented black beans in the fridge for maybe four months now and they're just fine. Read somewhere that they'll keep practically indefinitely if refrigerated. Perhaps the same is true of natto?

      1 Reply
      1. re: JoanN

        I believe the Chinese style black beans (as used in black bean sauces) are more heavily salted than natto.

        I have only bought natto frozen in the single serving foam containers. So I keep it in the freezer till I need my natto 'fix'.


      2. TOO LATE...natto's already spoiled!

        I've never known natto to spoil, but my grandmother used to say it got stronger, which probably means it continues to ferment.

        1. i worked for a sushi restaurant...and asked the same question to the itamae...he said a few months is another poster had replied its spoiled already.

          to be safe keep it in the freezer, which i do until use

          1. I do recall seeing dates on the package, as Ricepad said, I think it's more of a "best by.." date. You can always freeze it if you won't eat it quickly.


            2 Replies
            1. re: vf

              "Best by" date on natto -- isn't that an oxymoron?

              1. re: Larry

                I think that even if something is fermented to start with, at a certain point, all things kind of get funky. I recall having some gross natto growing up. I think it had been kept too long, so the beans were kind of dried out and shriveled (still stringy), but just not as plump and juicy as they could be.