While a few appropriately stored foods can last almost indefinitely— think white rice and honey — most consumables have a shelf life before they begin to spoil, lose flavor or grow stale. Many perishables come with advisory dates, which mostly aren’t required by law but are intended by manufacturers as good advice.
It’s a lot of advice, and much of it is confusing.
Use-by dates: Found mostly on dry goods like cereal and pasta, denoting the last date an item is expected to be at “peak quality.” It doesn’t necessarily mean the item isn’t edible after that date.
Sell-by dates: More a guide for retailers to signal when items need to be removed. It’s for inventory management, primarily since consumers are expected to buy and use items a few days past their “sell-by” date.
Best-if-used-by dates: Similar to “use-by” dates. The date when a product is expected to be at its freshest and tastiest.
Expiration dates: The only date with significant safety implications. If an expiration date has passed, there is a high likelihood the food has spoiled.