When you pick up a box of cereal or a carton of eggs, it might say any one of these: "Sell by," "Display until," "Best before," or "Use by."

The actual expiration date — when the food is no longer safe to eat — is often difficult to figure out.

To clear that up, 50 of the world’s biggest food and retail companies — including Campbell, Walmart, Kellogg, and Nestlé — are changing their expiration labels exclusively to "Use by" by 2020. The food retailers, which are part of the Consumer Goods Forum Board (CGFB), voted unanimously on the change September 20.

The board determined that confusing labeling is one of the leading causes of food waste around the world, since consumers might be unsure if a particular item still okay to eat. In the US, an estimated 40% of food that is bought is thrown out. Globally, about 1.3 billion tons of food are wasted, which contributes to 8% of annual greenhouse gases.

"Standardizing food date labels is a simple and effective way to reduce the amount of edible food thrown out by households, saving them money and reducing their environmental footprint," The Consumer Goods Forum said in a press release.

Beyond the environmental benefits, the board notes that simplifying labels could save consumers money. The average American family tosses out $1,500 worth of groceries annually, according to the forum. In the UK, that figure is $947.

In addition to the label change, the companies have devised a plan to educate consumers about food waste by partnering with manufacturers, government agencies, and NGOs.

There's a growing movement to reduce food waste at nearly every point in the supply chain, from the farm to the fridge. Some organizations are visiting farms to collect non-harvested crops for food banks. And startups, like Imperfect, are selling "ugly" fruits and veggies at lower prices that traditionally "beautiful" produce. The switch to "Use by" could be a simple change that builds on the fight against food waste.