A Guide to Expiration Dates

There’s no standardized system for food dating in this country, which means stamps on packaged foods can be baffling. Approximately 20 states require dates on some perishable foods, like meat and dairy. But depending on where you live, you may see “best if used by,” “sell by,” or nothing at all. (The one exception: infant formulas. Federal law requires an expiration date because the crucial nutritional benefits can deteriorate over time.) So what do the different labels mean? The most important are “use by” or “best if used by,” which are often included by the manufacturer to help consumers get top quality. An item will be freshest and tastiest if consumed by that date, but it will probably still be safe a few days after (stay within these food-storage guidelines). A “sell by” date is meant for the store; it tells a retailer when to pull an item from the shelves. When you buy packaged food, check to make sure the sell-by date hasn’t passed, then eat it within the time range recommended in this guide.

No, they can’t.

According to the USDA, high-acid canned goods, like tomatoes and citrus fruits, will keep for up to 1½ years. Low-acid canned goods—that’s pretty much everything else, including vegetables, meat, and fish—will last for up to 5 years. Canned foods are sterile, so they won’t host bacteria, but eventually the taste and texture of the items inside will deteriorate. Keep them at room temperature in a dark place, like a cabinet or a pantry. Of course, there’s no way to find out whether a canned food has gone south unless you open it, so if you can’t remember when you bought it and want to err on the safe side, throw it out (and replace it before hurricane season starts). And toss any cans that are bulging and leaking or that spurt liquid when opened. Although the toxin that causes botulism is extremely rare in commercial canned goods, damaged cans have a higher chance of being contaminated.

Items from the freezer section of the supermarket are safe to eat indefinitely. They have expiration dates because they won’t taste good forever; flavor and texture break down over time and because the package is exposed to air when you open and shut the freezer door. Once you open a bag of frozen peas or corn, pour out a portion rather than reaching in with your hand, which can introduce bacteria. (Bacteria can’t grow in the freezer, but they can survive. If you don’t cook an item after you defrost it, the bacteria could still be dangerous.) Leftover meals you freeze yourself should be tossed in 3 months. After that, they can become icy and start to take on the flavors of other foods in the freezer.

Have a giant pot of chili that would feed a team of football players? Invite them over. According to the USDA, most refrigerated leftovers last 4 days, tops. Dishes that contain seafood or uncooked ingredients, like mayonnaise, spoil faster; eat them within a couple of days. And don’t let uneaten food linger on the counter for more than 2 hours. The longer a dish sits at room temperature, the more susceptible it is to bacteria growth. Pay special attention to cooked rice and other grains, which at room temperature can harbor a bacterium called Bacillus cereus, which will make you sick. It’s fine to put warm food in the refrigerator or freezer. But when handling a dish that will take many hours to cool fully—a huge stockpot full of stew, say—transfer it to several smaller containers first.