Food is usually perfectly fine and safe to eat past the use by date.
The use by date on many foods is just a general guideline as to how long the food will stay fresh and doesn't always mean that the food is spoiled and unsafe to eat.
As long as you keep the food properly stored or refrigerated or frozen the food can be safely eaten weeks and even months past the use by date.
For example I've bought meats and froze them and eaten them a year later after the use by date has passed and it was still safe to eat.
Same with peanut butter and other foods that don't require refrigeration those foods were still safe to eat past the use by date although it was just not as fresh.