Do you throw away food when it hits its “use-by” date? If so, you’re unwittingly contributing to nearly half of America’s food supply being wasted every year.

It’s a simple misunderstanding that often trumps common sense. Most people think that if food products are past their use-by date, they’re not safe to eat. This isn’t true, though.

The use-by date refers to a food product’s peak freshness. That milk might taste a little stale a week after the date printed on the carton, but it’s really not unsafe until it turns into cottage cheese.

Still, this simple misunderstanding is contributing to millions of pounds of food being wasted every single year in America, according to a new reports from the Natural Resources Defense Council and Harvard Law School’s Food Law and Policy Clinic.

Certain foods are edible long after their use-by date has come and gone, too. Eggs, for example, can be eaten up to five weeks after they’re bought, even though the use-by comes much earlier. A box of macaroni and cheese that has a use-by date of today can still be enjoyed next year, with no noticeable changes in taste or quality.

Still, 90 percent of Americans throw away food prematurely. One of the study’s co-authors suggested that food manufacturers merely need to clarify their labels better.

“We are fine with there being quality or freshness dates as long as it is clearly communicated to consumers, and they are educated about what that means,” said Emily Broad Leib, the director of Harvard Food Law & Policy Clinic.

“There should be a standard date and wording that is used. This is about quality, not safety. You can make your own decision about whether a food still has an edible quality that’s acceptable to you.”

Solving the problem is complicated, but here’s a quick cheat sheet for you until they manage to figure it out:

“Use by” is a label intended for your use, but intended from the manufacturer as a marker for when the food reaches peak freshness. It doesn’t indicate when food spoils, and doesn’t necessarily mean that food is not safe to eat after the date. Use your common sense.

“Best by” means the same thing, but it’s probably a little clearer for the consumer.

“Sell by” is strictly for the manufacturer. It doesn’t mean that the food is spoiled after the “sell by” date, it just helps manufacturers and store owners keep track of product turnover. It’s not for you at all, so don’t worry about it.

You can read the entire report on “use by” date confusion here, or check out a guide to know when common foods are spoiled here.

[Image: Shutterstock]