As it turns out, they don’t have as much to do with food safety as you’d think, and the chances of getting sick from eating a yogurt a couple of days past its expiration date are pretty slim. This is because, except for infant formula, expiration dates aren’t required or regulated by law on products and are determined by the manufacturer. “Food dating is more about food quality than food safety,” says Janilyn Hutchings, a food scientist and certified professional in food safety who works for StateFoodSafety. “With the exception of baby formula, the food dating system is not government-regulated or standardized, so the dates printed on most items are actually suggestions from the manufacturer to help you know when the product is at its best quality.” According to Jennifer Kaplan, a food systems instructor at the Culinary Institute of America in St. Helena, California, expiration dates are “a manufacturer’s vague estimate of when the product is at its ‘freshest.’ Many foods will still be good to eat days, weeks, or months after those dates,” she says. This doesn’t necessarily mean you should completely ignore expiration dates, but think of them more as guidelines than as hard rules about when food is safe to eat. “It is safest not to use food after the “Use by” date, especially if you work in retail food service, because expired food is more likely to be spoiled,” Hutchings says. “If the food has become rancid or spoiled, no amount of cooking can guarantee the food will be safe to eat.” There are obviously some risks to consider when it comes to eating expired food. For example, canned foods and non-perishable products are likely to last long past their expiration dates, but you should pay more attention to the expiration dates on foods that spoil more easily, like fresh fruits and vegetables, or eggs. If you do eat spoiled food, you could become seriously sick. Your food can become less nutritious the longer it sits around. That’s one of the reasons the U.S. Department of Agriculture does regulate the expiration dates on infant formula—past the expiration date, there’s no guarantee that the formula matches the nutrition information on the packaging. And as you probably know, you should immediately toss out any food that’s growing mold, or that has an odor. “Always watch for warning signs like odors, flavors and colors that don’t look, smell or taste right, and discard immediately, regardless of the date on the label,” says Dr. Luiza Petre, a cardiologist who also specializes in nutrition, weight management, and wellness. After all, if food isn’t properly stored or packaged, it can go bad even before the expiration date. But as long as you aren’t seeing any signs of spoilage, most foods should still be good to eat well past their expiration dates (good news for that bottle of ketchup in your fridge). “Non-perishables can be kept and consumed past the expiration date with only taste, quality and nutrition compromised,” Petre says. So while non-perishables, like chips, might go stale over time, they shouldn’t be unsafe to eat after their expiration. And according to the USDA, you can even donate food after the expiration date has passed. There’s no guarantee that food banks will use them (they’ll evaluate your donated items on their own), but if there aren’t any signs that the food has spoiled, it should still be safe to eat.

The Difference Between Expiration Dates

Since expiration dates are decided by the manufacturer, there’s no standard that’s used across the board, which is why you’ll see “best by,” “use by,” “sell by,” and other variations. Each one means something a little different, but none are true “expiration” dates, so don’t toss your groceries if you have something a day or two past its stamped-on date. According to Hutchings, “The ‘best by’ date gives the consumer a deadline for when the product will have the best flavor or quality.” Products past their “best by” dates should still be safe to eat (as long there aren’t any signs of spoilage), but they might taste a little less than fresh, since they’re the manufacturer’s best estimate of when their product will still be the best quality. In contrast, “sell by” dates are really more for stores than consumers. According to the USDA, “sell by” dates tell grocery stores and other retailers how long the product should be on display and available for sale. It’s also not a measure of safety, and most products should be good even after the “sell by” date has passed. “The ‘use by’ date tells the consumer the last date the product will be at its peak quality,” Hutchings says. And according the USDA, “use by” dates are only a measure of safety when they’re used on infant formula. All other products should still be safe to eat. Again, there’s no guarantee that food will always be safe to eat after its expiration date, but if food safety guidelines aren’t followed, it could easily have gone bad before its expiration date. “The sniff test remains the best gauge,” Kaplan says, so if it looks and smells good, your food is still probably safe to eat. Of course, it’s still best to err on the side of caution to avoid getting sick, so if you have any doubts about the safety or quality of your food, toss it out. But if you have a carton of yogurt that’s just past its “best by” date, you don’t have to let it go to waste.