- The precise answer to the question ? How long does peanut butter last once opened? depends to a large extent on storage conditions - keep opened peanut butter tightly covered at all times and store in a cool, dark area.
Pantry storage will allow opened peanut butter to spread more easily; about 3 months after opening, refrigeration is recommended to help retain the peanut butter™s flavor and prevent oil separation.
Storage time shown is for best quality only - after that, the opened peanut butter's texture, color or flavor may change, but in most cases, it will still be safe to consume if it has been kept continuously refrigerated.
"Best By," "Best if Used By," and "Use By" dates on commercially packaged foods sold in the United States represent the manufacturer's estimate of how long the product will remain at peak quality - in most cases, the opened peanut butter will still be safe to consume after that date, as long as it has been stored properly and kept continuously refrigerated after opening.
How can you tell if peanut butter has gone bad? If peanut butter develops an off odor, flavor or appearance, it should be discarded for quality purposes; if mold appears, discard the entire product.
Sources: For details about data sources used for food storage information, please click here