Some of us adhere to them with religious severity and others use them as an insignificant suggestion, but either way, expiration dates are mysterious. They seem to suggest that we should stay far away from foods marked with a calendar date that's passed, but is that what they really mean?

According to the USDA, expiration dates are not a safety date. However, the USDA does recommend that if a product has a "use-by" date, you should follow that date . They also define the different expiration terminology. The "Sell-By" date suggests you buy the product before the printed date, but it doesn't indicate that the product has spoiled. And the "Best if Used By" date suggests consuming that product before the date for optimal quality.

But the amount of time an item stays safe to eat largely depends on how it is stored, not how long it's been produced for. Milk kept in the fridge will unquestionably last significantly longer than milk left out on the kitchen counter.

And since "more than three-quarters of U.S. consumers mistakenly believe certain foods are unsafe to eat after the expiration date has passed," reports The Boston Globe, we feel that it's time to get the facts straight. Don't waste your money by throwing out foods with expired dates. Click through the slideshow below to see how long common grocery store items remain safe to eat.

The information for the life span of food items was found on StillTasty.com . If curious about the expiration dates on other products, visit their site for more information.