I opened a new bag of dried black beans that had been in my cupboard for a while that had a bit of air in the bag. When I opened them I almost smelled mold but not really. I found one moldy bean and the rest looked fine. I didn't really smell mold but maybe almost did. Is mold obvious and I wonder if the air in the top of the bag means anything? I don't want to waste the beans but also don't want to eat mold toxins. Thanks!