I’m not an expert, but I’ve read that if you’re fermenting foods properly it’s very hard to make yourself sick because the lactobacillus culture grows quickly enough to overpower any botulism that could try to colonize it. Just make sure there’s not mold growing on top.

I don’t believe that applies to food stored in oil, but I’m not sure.

Edit: I looked it up and miso is fermented by aspergillus oryzae, but the same principle would apply.