When Do Foods Actually Expire?

There is a difference between "use by," "sell by," and "best before" dates, phrases we often see instead of "expiration." Sell by dates tell a retailer when to discount or remove a product from the shelves. Theoretically, this is not when the food is no longer good, but rather when, practically speaking, a customer would no longer be able to consume it before it expired. Best before or use by dates mean what they imply: the quality of the product may begin to decline after this date, becoming stale or dry, for instance, but not necessarily dangerous. Depending on where you live, you may also see terms such as “born on” and “guaranteed fresh until,” the latter of which is primarily for baked goods. All of these dates, however, can be viewed as warnings rather than signs of danger.

Throwing away food contributes to waste, for which North Americans are quite guilty. A recent study funded by the United States Department of Agriculture found the average American wastes one pound of food per day. This means the country wastes approximately 20% of food purchased each year. In many cases, this is due to misunderstandings and misinformation about expiration dates. Many foods can still be used past the date on the can or bag.

Because cheesemakers use processes like curdling to make cheese, a word we usually associate with foods that have gone bad, this dairy product is one for which some people find it easy to overlook expiry dates. While the mold on blue cheese is safe to eat, and the mold cheddar might develop after months in the fridge may not be, many experts confirm that you can safely cut around moldy parts of cheese, allowing about an inch of leeway, and use the rest. This does not apply to soft cheeses, however.

Stale bread can be hard to chew or less than tasty, but it is often not bad for you. A sniff test is one way to determine the edibility of bread -- if it smells sour or moldy, it could be harmful. Otherwise, consider making toast or a reciple such as bread pudding with the last slices of stale bread.

The sniff test doesn't always work for dairy, since many of us are guilty of imagined rancid scents after seeing a past date on the carton. Yogurt is even more difficult, given its already sour smell. Due to the same processes that deliver its signature scent, however, yogurt is usually good for up to a few weeks past its expiration date. The exception to this rule is yogurt -- or any dairy product -- that has been left out of the fridge for more than an hour, even unopened.

Most of us have the tendency to keep condiments in the kitchen cupboard so long that we forget they're there. But that actually works out in our favor. Plenty of unopened condiments like mustard, ketchup, mayo, and even salad dressings are fine beyond their expiration date. Even once a condiment has been opened, as long as it is stored in the fridge, a visual or nasal investigation should indicate whether or not they are ok to eat. Remember that some foods separate, developing an oily or watery film on the surface, but this does not mean the sauce has gone off.

Even the dates on bags of pasta usually indicate a shelf life of a couple of years. However, this is another food that is often good for much longer. Dry pasta does not contain water, so as long as you store it in a cool and dry place, the best by date can be shy by as much as a few years. Fresh pasta, on the other hand, spoils quite quickly, though as long as it is stored properly, it may be good two or three weeks after its expiration date.

Wilted lettuce gets a bad reputation. However, just because greens have begun to droop doesn't mean they have become inedible. As with most fruits and vegetables, a little bruising does not mean that the food has gone bad. In fact, fresh produce has one of the more simpler means of judging its expiration date: If it's rotten, throw it out. If not, use it. One thing to keep in mind when it comes to produce, however: nutrients begin to degrade as soon as a fruit or vegetable leaves the soil, so fresher product will be more nutrient-rich.