Hello! I'm not an expert, but I found this:

Grocery product shelf life is based upon the Manufacturer’s Date Packaged (DP) code. Manufacturers encode the Date Packaged somewhere on the product in a form unique to their internal procedures. My objective is to provide Date Packaged (DP) code keys for well-known products to assist your food purchasing and rotation efforts. Remember that these timeframes are the manufacturer’s recommendations for MAXIMUM freshness and nutrient value. Several vendors indicated their products are edible long beyond the published recommendation dates....continued here:

http://www.a1usa.net/gary/expire.html