Ever wonder what stores do with leftover meat, milk, muffins, and canned goods that have stuck around beyond their sell-by or use-by dates? After Consumer Reports mystery shoppers recently discovered 72 products past their prime in 31 stores across seven states, we asked food industry insiders for the scoop.

As long as the food isn’t spoiled—many date codes indicate when an item is apt to be fresh and flavorful rather than unfit for consumption—many retailers and manufacturers use the expiring goods for grocery donations to hunger-relief charities. (For information on how long products stay good enough to eat, go to www.fsis.usda.gov and enter the search term “food product dating.”)

Feeding America (formerly known as America’s Second Harvest) is the largest grocery donations operation in the U.S. It distributes more than 2 billion pounds of donated groceries per year to 200 food banks, which work with community-based food pantries and soup kitchens to feed the ­hungry. It’s the supermarket industry’s ­preferred channel of distribution for “unsalable” products, according to Troy Beeler, senior manager of sales and sales promotion for the Grocery Manufacturers Association, a trade group.

Feeding America works with almost every major food manufacturer and grocery chain, as well as the agricultural industry, to collect items that aren’t suitable for retail sale but are still “safe and nutritious,” says Ross Fraser, the operation’s spokesman. Besides expiring goods, the mix of grocery donations includes bruised produce, items with missing labels, overstocks, and discontinued merchandise. Feeding America asks supermarkets to freeze fresh meat shortly before its sell-by date, which provides an extra 60 to 90 days to distribute the food.

Some stores make grocery donations directly to local groups. Florida-based Publix, for example, gives store-made baked goods to homeless shelters, food pantries, after-school centers, and churches. And some foods are tossed. Costco is reluctant to give away leftover rotisserie chickens out of safety concerns over how they’re handled once they leave the store.

There’s no way of knowing the used/tossed ratio, but stores are trying to better match supply with demand and reduce the amount of expiring food.

For many years, supermarkets were reluctant to donate perishables because executives worried about lawsuits stemming from consumption of bad food—even if spoilage occurred after the products left the store. But the federal Good Samaritan Food Donation Act, which was signed into law in 1996, allayed many fears by shielding companies from liability as long as the food was donated in good faith.