Should You Ignore Expiration Dates?

A new report exposes what they really mean

September 19, 2013
food expiration date

You might think that "use-by" and "sell-by" dates stamped on food packages are there to protect you from spoiled eggs, rotten meat, or rancid milk. But guess what? Those two words are absolutely meaningless, according to a new analysis from the Natural Resources Defense Council (NRDC) and Harvard Law School. Not only are the dates not protecting you from unsafe edibles, but they're also causing Americans to waste a ton of money and food.

"Every entity around the world that has investigated food waste has highlighted expiration dates as key in reducing food waste," says Dana Gunders, one of the report's coauthors and a food and agriculture staff scientist at NRDC. As it is, 40% of the food produced in the U.S. never gets eaten—and that's a lot of water, fuel, and land devoted to food that goes from farm to trash can.


Research from the United Kingdom has shown that 20% of food waste there can be attributed to confusion over "use-by" and "sell-by" dates. Though no similar figures exist yet for the U.S., Gunders says that if those numbers were applied here, it would mean that the average American household wastes up to $455 every year because of those meaningless date labels. And, she adds, surveys indicate that 90% of Americans have thrown out food at least once because it was past its use-by or sell-by date, even though they probably didn't need to.

More From Prevention: Food Labels Can Trick Consumers 

It's not just consumers, though. According to a 2001 report that NRDC discovered, businesses waste $900 million every year tossing food that they're prohibited from selling after the use-by or sell-by dates. That's the most recent figure available, but "now that more products have dates and more states require dates, so I'm sure that number has skyrocketed," says Emily M. Broad Leib, lead author of the report and director of Harvard Law School's Food Law and Policy Clinic.

Here are five more little-known facts about sell-by dates from NRDC's report:

#1: Date labels are used to indicate freshness, NOT food safety. It all started back in the 1970s, when Americans were moving farther away from the source of their food. "As Americans left farms and moved to cities, they wanted indicators of food-product freshness," explains Broad Leib. The dates were never meant to be indicators of food safety, but as the practice grew, more and more people assumed that was their purpose. Now surveys show that more than half of American adults assume that sell-by, best-by, and use-by dates all indicate the date past which foods are no longer safe to consume.

#2: Date labels aren't legally defined. Despite the fact that both the Food and Drug Administration (FDA) and the U.S. Department of Agriculture have the power to define and regulate date labels, neither agency does (except for infant formula, which the FDA requires expiration dates on because the nutrients begin deteriorating after a certain period of time, not for safety reasons). Definitions are left entirely to the industry to define, and manufacturers—and even retailers—rarely distinguish between "sell by," "use by," and "best by."

In general, sell-by dates are intended for stores, not customers. Manufacturers want to ensure that you're buying a product that tastes as good as they'd like it to; for quality reasons, they don't want stores selling their products after those dates. Most products are good for a reasonable amount of time after the sell-by date.

"Use by" and "best by" are used interchangeably as an estimate of the date after which a food will no longer be at peak flavor.

(However, these are just general guidelines, and not true in every situation or every instance.)

#3: Every manufacturer has a different way of determining the dates. Not only do manufacturers not use a standard definition for these labels, but they also have their own ways of coming up with the dates. Some base them on consumer taste tests, which are subjective and not reliable, says Gunderson, while others use laboratory testing to see how long a product can sit on a shelf before its quality deteriorates. Still others use scientific literature to come up with general estimates of how long their products will last. "I would guess that 80% of dates are guesses based on what their competitors are doing," adds Ted Labuza, PhD, a food safety expert and professor of food science and engineering at the University of Minnesota, who contributed to the report. Companies don't have to disclose their testing procedures, so you'll never know how a manufacturer set that date.

#4: States have their own rules and requirements that govern date labels. Confused enough? There's more: states have started to use these dates to come up with a patchwork of laws that add to more food waste and don't prevent foodborne illness. Twenty states and the District of Columbia have laws prohibiting the sale of foods past the sell-by or use-by date, while 30 don't. "I don't know of any food poisoning outbreaks caused by people eating food past its expiration date," says Dr. Labuza.

#5: The dates are leading to a host of problems. All of this mass confusion means mounds of food waste, which is now the number-one source of garbage in landfills, kicking up 17% of U.S. methane emissions. (Methane is a globe-warming greenhouse gas more potent than carbon dioxide.) It's also hindering recycling: Because many people throw out containers half-filled with food, the containers can't be recycled, which adds to other forms of solid waste in landfills, says Gunderson. Finally, the dates could actually be putting you at risk for foodborne illness. When consumers rely upon these arbitrary dates, they avoid using other much more reliable indicators of food spoilage, such as slimy texture, off odors and flavors, or altered colors, to determine whether a food is really safe to eat.

More from Prevention: How To Waste Less Food 

What can be done?  "With so many Americans in need of food, it makes zero sense to throw away perfectly good food," says Gunderson. She says NRDC would like to see a federal date-labeling standard set, or at the very least, an industrywide adoption of some form of labeling standard that is useful to consumers—one that indicates both freshness and food safety.

Until that happens, "we encourage people to test the quality for themselves rather than toss it," she says.

"Foodborne illness doesn't come from products being too old," says Dr. Labuza. If dangerous pathogens exist in a food product, they can likely make you sick long before you reach a product's expiration date. His tips on DIY date testing: 

  • Stay outside the "danger zone." The temperature range of 40°F to 120°F is ideal for disease-causing bacteria to proliferate. Refrigerate your food as soon as you get it home and cook it thoroughly. Be sure to refrigerate your leftovers promptly.
  • Make sure your fridge is chilly. "I set my refrigerator to 34ºF," says Dr. Labuza. The lower the temperature, the better, he says. Not only will colder temperatures prevent bacteria from multiplying, but they'll also extend the shelf lives of perishable goods you might not cook, such as milk and fresh produce.
  • Pay attention to COT. That's color, odor, and texture. "Fresh foods that spoil quickly all have a high water content," notes Dr. Labuza. They'll spoil due to microbial growth or other reactions in the foods that lead to strong odors, slimy textures, and changes in the food's original color—the browning of banana peels, for instance. Pay attention to changes in quality before you toss a food based on an arbitrary date.

More from Prevention: How To Prevent Food Spoiling 

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