A customer scans the expiration dates on gallons of milk...

A customer scans the expiration dates on gallons of milk at a Safeway grocery store in Washington, D.C. on Aug. 20, 2007. Credit: Getty Images

Is there a difference between a product's "sell by" date and "use by" date?

Yes. Emphatically. The "sell by" date is aimed at the retailer, signaling to a grocery store when the product should be off the shelf. Once that product gets home, its "use by" or "best before" date provides a guide to when it is best eaten.

Confusion over these two types of dates is rampant, according to "The Dating Game," a just-released report co-authored by the Natural Resources Defense Council and Harvard Law School's Food Law and Policy Clinic. And the upshot is that up to 90 percent of Americans throw out perfectly good food, leading to an estimated $165 billion worth of edible food that gets trashed every year.

What's more, "use by" dates are not regulated by the federal government; manufacturers decide when a given product has expired, sometimes guided by individual state regulations, sometimes by their own undisclosed systems. (One notable exception: infant formula is subject to explicit Food and Drug Administration labeling requirements.)

According to the report, "the current system of expiration dates misleads consumers to believe they must discard food in order to protect their own safety. In fact, the dates are only suggestions by the manufacturer when the food is at its peak quality, not when it is unsafe to eat."

"The Dating Game" makes a number of sensible proposals for bringing order to this chaos. (You can read the 64-page report at bit.ly/1b2Edg0.) But it offers no practical advice for judging whether to toss your particular bag of pretzels.

The best resource I've found for food-storage issues is the website StillTasty: Your Ultimate Shelf Life Guide, which gathers information from various government sources (U.S. Department of Agriculture, FDA, Centers for Disease Control) as well as nonprofits and the food manufacturers themselves.

At stilltasty.com, you can look up thousands of food products and learn how long they will last -- both opened and unopened -- and where they are best stored, pantry or refrigerator. Plus, there are scores of helpful features. Wondering whether to store bread in the refrigerator or on the counter? "The counter is definitely the better place for your bread. Bread stored in the refrigerator will dry out and become stale much faster than bread stored at room temperature. For longer-term storage, you should freeze bread."

Trouble keeping ice crystals out of ice cream? "Once you've opened a new container of ice cream, press some plastic wrap over the surface of the remaining ice cream before re-closing the package. Return the ice cream to the freezer and use within one to two months."

StillTasty says that, unopened, pretzels should last about nine months in the pantry; opened, one to two weeks.

Crisp apples

And speaking of storage, apple season is upon us, and the best way to keep an apple crisp is to keep it cold.

Commercial packers hold their apples just above freezing temperatures, and this can prolong their crispness for months. As soon as you get apples home, refrigerate them. A market that cares about its apples will ideally display them in a chilled case. When I buy apples, I try to buy only those that are cold to the touch. Warm apples do not make it into my shopping cart.

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