Probably not. Supposedly some mold grows on peanuts that releases and carcinogenic toxin. 100% serious. Read the article like yesterday.
* "Sell by" date. This tells the store how long to hold the food for sale. Don't buy the product after this date. Food sold on the "sell by " date can still be eaten later. For example, milk generally is safe and wholesome 7 to 10 days after the date on the label. This is a "sell by" date for the grocery store, not a "use by" date for the consumer.
* "Freshness" date or "quality assurance" date. This date suggests how long the manufacturer thinks the food will remain at peak quality. The label might read "Best if used by November, 2005." The product still may be used after this date, although it may no longer meet the company's standard for freshness.
* "Pack" date or "package" date. This is the date the food was packaged or processed. With this information, consumers can decide which package is fresher. Fresh meat is labeled with a pack date. Do not buy ground beef packaged three days ago when a package is available that was packed today.
* "Expiration" date. This is the last date the product should be eaten. It might read, "Do not use after March, 2005." Always discard food that has passed the expiration date.
$2 for a tasty new jar. I recommend Trader Joe's if they got one near you.
Pretty sure that means expired peanut butter is fine unless it smells/tastes rancid. However I wouldn't risk it simply due to how it would taste since it's almost surely rancid. A few days sure but 5 months?