http://www.emoryhealthcare.org/HealthGate/42284.html
Looks like you might still be OK:
Pantry, or shelf stable (non-perishable) foods, like cereal, baking mixes, and peanut butter may display ?best if used by (or before)? dates. These indicate the shelf-life of a product?they tell you when a product is no longer at peak flavor, texture, and appearance. You can safely eat most of these types of foods past their listed date if they?ve been stored properly, but they may not taste their best or be as nutritious.