The next time you start to toss an “expired” carton of milk, consider this: Dates on packages don’t actually have anything to do with food safety or FDA regulations. Instead, the dates are a somewhat arbitrary indication of when a manufacturer thinks food might be freshest, and most food will likely be fine for days or weeks afterward.

Misleading labels are one reason that consumers waste nearly 40 percent of the food they buy — and one of the inspirations behind Bump Mark, a new bio-based food label made with gelatin. As the food in a package starts to decay, so does the gelatin; when it finally expires, the gelatin reveals a layer of bumps. If the label is still smooth, a consumer finally knows unequivocally that food is still safe to eat.

“Because gelatin is a food, the same things affect it as the food inside a package,” explains London-based designer Solveiga Pakstaite, a finalist for the James Dyson Award. “It has an interesting property that when it expires, it turns back into a liquid. I couldn’t just use any natural substance — it had to be one that changes its state.”

By changing the concentration of gelatin, the designer can match the label to specific foods. A weak concentration breaks down faster, and works for foods such as milk and meats that don’t last as long. For any given food, the label can be adjusted to degrade at exactly the same rate. “You can actually adapt this to any kind of product,” Pakstaite says.

The bump-filled design was originally created for visually impaired consumers, who have no way to read current expiration labels. But Pakstaite quickly realized that the system would be a more accurate solution for everyone.

“I don’t think that current [expiration] dates are effective at all,” she says. “Safe food is being thrown away unnecessarily. So I got completely obsessed with the idea of being able to track the condition of the food.”

In the United States, dates on food have only been around since the 1970s. A handful of states require dates on certain products, but other than infant formula, none of the dates are regulated by the FDA.

“There’s this mass confusion and misinterpretation happening around the dates, because consumers think the dates are telling them the products are bad, when in fact that’s not even what they’re meant to convey,” says Dana Gunders, a staff scientist at Natural Resources Defense Council who co-authored a report called The Dating Game about how food date labels lead to food waste.

“Sell-by” dates tell retailers when to sell something in the store — meaning food might be good for a week or even longer afterward. But consumers tend to see the date as a sign to immediately throw food out. Manufacturers use a mix of other messages, from “best by” to “enjoy by” to “best before,” to suggest when food might be at its tastiest. But those labels also don’t mean that food is bad.

“If you’re a manufacturer, you don’t know how consumers are going to handle your product,” Gunders says. “So manufacturers often are setting those dates based on the worst-case scenario. So they’re thinking about the mom who goes shopping and leaves her groceries in the car while she’s watching her kid’s soccer game. They’ll consider those types of mishandling while setting dates.”

Unlike a printed label, the Bump Mark automatically adjusts if food is left out too long. That means consumers also have a clear indication if food was mishandled before it got to the store.

“If the retailer is using this, they’re going to have to store it in conditions such that when it’s on the shelf, that label is still smooth, and people are going to be reassured that it is in fact still safe to eat,” Pakstaite says. “There’s such a huge mistrust of retailers, especially after the recent horsemeat scandal in the UK. I think that retailers probably want to buy into anything that would help build trust.”

Though the label would cost more than a simple printed sticker, Pakstaite says that it will be cheaper than other alternatives. She will calculate exact costs after she begins working with a retailer to finalize specific materials and quantities. “It’s incredibly low-cost considering the fact that many retailers have been trying to implement RFID and electronics-based solutions for this,” she explains. “They would be far more expensive than just jelly and a bit of plastic are going to be.”

Pakstaite is patenting the design and looking for a commercial partner to help bring it to life. She hopes that it can help reduce the enormous amounts of food that end up unnecessarily in the trash. In the United States, nine out of 10 people throw out food early because of confusion over dates. For the average family of four, that can add up to several hundred dollars’ worth of food — and the huge environmental footprint of growing food that goes straight to the trash.