For the exception of infant formula, food expiration dates are not required by federal law. Some states require particular products to carry “use by” dates or “sell before” dates. These dates are actually not for the consumer, but are mainly for the retailer to judge when a product should be pulled from the shelf.
“Open dating” is used for perishable items. Once this date has past, the quality of the food may diminished, but it is not an absolute “expiration date,” for the product. If proper refrigeration has occurred, most perishable items will be consumable beyond the stamped date.
“Closed/coded dates” are used for shelf stable items, such as rice and flour. These dates are coded for the benefit of the manufacture for interstate commerce travel. This also helps the manufacture rotate their inventory and track products in the event of a food recall.
All perishable items should be refrigerated or frozen immediately upon returning home from shopping. If properly stored and packaged, frozen foods can last indefinitely. Canned or shelf stable items should be kept in a dry space, 50-70 degrees Fahrenheit. They should not be kept in a cellar, basement or crawl space. Moisture is the enemy of these products. Do not purchase canned goods that have been dented or damaged. This can compromise the packaging of the product and its sustainability. High acidic items such as tomato sauce will keep for 18 months; canned beans, if properly packaged will keep for 5 years. 
The Food and Drug Administration recommends the following guidelines for perishable items:
Milk – will last for approximately one week after “sell date,” if properly refrigerated between uses.
Eggs – will keep for 3-5 weeks after their “sell by date.” Grade A eggs will decrease in freshness, but still will be edible.
Poultry or Seafood – should be used 1-2 days after purchase, unless frozen immediately. Make sure to prep the poultry or seafood in an air-tight storage device before freezing.
Beef and pork – should be cooked 3-5 days after purchase, unless frozen immediately. Again, make sure to package the meat in an air tight container or food storage bag before freezing.