“Sell by.” “Use by.” “Best by.” These terms and their many variations have probably caused you to toss perfectly good food just because the date on the label has passed. Nearly 85 percent of consumers have thrown out food based on these designations, contributing to a widespread food waste problem in the United States. A recent report from ReFED, a coalition of businesses, NGOs and other organizations fighting food waste, calculated that date labels alone cost American consumers almost $30 billion annually.

Not only is this rampant food waste appalling in a nation where 42.2 million people live in food-insecure households, the USDA notes that food waste has far-reaching impacts on resource conservation and climate change.

Food waste is the largest component of U.S. municipal solid waste. As uneaten food rots in landfills, it releases the potent greenhouse gas, methane, which is a cause of global warming. That’s not to mention the sheer amount of labor and precious resources such as water, land and fuel that goes towards cultivating, packaging, transporting and processing food that’s ultimately never consumed.

The problem with date labels is the lack of an official guideline. Besides baby formula, product dating is not generally required by federal law. Under the current open dating system, some food manufacturers or retailers stamp a date onto a product based on an estimation of peak freshness, not if it’s safe to eat.

The sell-by date is actually an approximation that manufacturers advise to retailers on how long they should keep items on shelves. Eggs, for instance, are usually safe to consume at least three to five weeks after the sell-by date, food safety experts advise. “Use by” or “Best by” is the date when you should eat or freeze a product for ideal quality. For example, crackers or potato chips may not be as crispy after the indicated date.

All this means is that food that has gone past its expiration date has not necessarily gone bad.

“Foodborne illness comes from contamination, not from the natural process of decay,” according to Dana Gunders, a staff scientist at the Natural Resources Defense Council.

Unfortunately, many consumers do not realize how uneaten eggs or chips can affect the well-being of the planet.

“People haven’t quite made the link between food waste and the environmental consequences of food waste,” said Brian Roe, an Ohio State University professor and co-author of a PLOS ONE study that found less than 60 percent of Americans understand that wasting food is bad for the environment.

So how exactly did food date labeling become a thing? As the Harvard Food Law and Policy Clinic and the Natural Resources Defense Council detailed in a joint study, back in the 1970s (when people started to buy foods from the grocery stores instead of growing their own), they also started to demand accessible indicators of product freshness and quality. In response, supermarkets adopted the open dating system.

"Items at the grocery store are stamped with a jumble of arbitrary food date labels that are not based on safety or science," said Sen. Richard Blumenthal, D-Conn., who introduced a bill last year to create a standard federal date labeling system. "This dizzying patchwork confuses consumers, results in food waste, and prevents good food from being donated to those who need it most."

The hodgepodge of food dating labels we see today is something 37 percent of Americans apparently treat as law. A 2016 Food and Health Survey found that the expiration date is the most important consideration for food purchases for 7 in 10 consumers.

Even the food industry—which ostensibly profits off of misleading expiration labels—admits standardizing food dating is necessary. This past February, the highly influential Grocery Manufacturers Association and the Food Marketing Institute advised its members, some of the biggest food and beverage giants in the industry, to streamline date labels to just two standard phrases: “Best If Used By” (to describe product quality), and “Use By” (to describe products that should be consumed by the date listed on the package and disposed of after that date).

ReFED determined in its report that standardization could prevent 8 million pounds of food from getting thrown out prematurely.

Meanwhile, there are scores of online guides that can help you determine if an “expired” food is still safe to eat, as well as tips on how to extend a product’s shelf life. While you should consume at your own risk, use your eyes, nose and taste buds to determine whether a food item is still fresh. So if it looks fuzzy, smells funny or tastes weird, you should toss it.

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Infographic created by uniPoint.