Some foods practically tell you when to throw them out - they stink, they are covered in mold, or they change colors. This is not the case with peanut butter.
Peanut butter seldom molds because despite feeling wet and greasy, it is actually extremely dry. Peanut butter separates, but that just means it's time to shake it up.
Your peanut butter can, however, become rancid after 9-12 months of sitting around. Among many other facts, Live Science tells us that rancid peanut butter actually won't hurt you if you eat it. It just tastes bad.
In short, if your peanut butter tastes bad, dump it. Otherwise, you can worry about your strange taste buds but you don't need to worry about getting sick.
We once had a jar of peanut butter for over 5 years. We didn't eat from it, but we coated our dog's medicine with it so that he would eat it. Scruffles didn't have any problem with the taste.
What's the longest you've had a jar of peanut butter?
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