They do have an expiration date on them so maybe? I've never had a peanut go bad, but then again I eat a bottle about every two weeks, so my supply stays rotated. *found this online >Rancid peanuts taste harsh and bitter. They might also smell like old paint or putty, but that's not always easily discernible. Shelled peanuts keep for about 4 months at room temperature and 12 months in the fridge. Unshelled ones last around 6 months unrefrigerated and more than a year refrigerated.