Forget about clipping coupons or buying store-brands to save money on groceries - at least for a moment.

There’s another secret to saving cash at the supermarket - avoiding food waste.

Building leftovers into your meal plan is one way to combat food waste, but if you’re a stickler for following the expiration dates on foods, you might be wasting more food - and money - than you ever realized.

It turns out, not all food expiration dates are created equal.

Manufacturers stamp “best by,” “use by” and “sell by” dates on everything from eggs to canned goods, but the meaning of those dates can be confusing, if not misleading.

So how do you know whether those eggs you bought last month are still good? Or what about the box of cereal dated July 2013 that you just discovered in the back of the pantry?

It pays to know your terminology.

Here’s a quick primer, according to the U.S. Department of Agriculture:

  • A "sell by" date tells retailers how long to display products for sale.
  • A "best if used by" date is recommended for peak flavor or quality. "It is not a purchase or safety date," the agriculture department said.
  • A "use by" date is the "last date recommended for the use of the product while at peak quality." The manufacturer sets the date.

Further, according to the Food and Drug Administration website, food dating “is entirely at the discretion of the manufacturer,” with the exception of infant formula.

In other words, food dates have more to do with food quality and store inventories than food safety.

Eggs, for example, are typically good for three to five weeks after purchase.

Fresh poultry should be cooked within two days of the package date. Stick it in the freezer and you have up to a year to cook it.

Cream cheese in foil wrap is usually good three to four weeks beyond the date or two months if frozen.

And that box of cereal from the back of the pantry? It’s typically good for six to eight months beyond the date.

If in doubt, look it up.

The agriculture department has a list of guidelines and a chart of storage times on its website (1.usa.gov/MWVr7D). Keep in mind, the food must be stored properly to have a longer shelf life.

Even more user friendly is the site EatByDate.com, which has a handy search engine that not only estimates the true shelf life of foods but also recommends proper food storage methods and other food-safety tips.