Experts: 'Sell By' Dates Don't Necessarily Mean Groceries Have Gone Bad

NEW YORK (CBSNewYork) -- From milk to meats, salad to cereal, if it's in the grocery store, it has a date printed on it.

Some items say "use by," others are marked "sell by," and some simply have a date.

"I don't want to eat something that's expired," said shopper Christina Guzman.

But Peter Lehner, executive director of the National Resources Defense Council, noted that the dates are not expiration dates.

"You don't need to throw it out if it's past the date on the label," he told CBS2's Kris Van Cleave.

The NRDC estimates nine out of 10 Americans are confused by the dates. A family of four throws about $2,000 worth of still-edible food away every year.

"The dates are up to the manufacturers," Lehner said. "There's no federal standards for anything in this store except for infant formula."

Lehner said many foods, if stored properly, can last long after the labels say.

For example:
• Milk can last at least a week past the printed date
• Eggs can still be good three to five weeks after you buy them
• And many canned products last up to five years.

The Grocery Manufacturers Association said the dates indicate freshness, but it admits changes are needed.

"We are working to improve current code dating practices, with the goal of creating a uniform, global standard that will make it easier to interpret date labels," the group said in a statement.

Lehner said, until then, consumers should use common sense.

"You can open it and smell it," he said. "You can take a look at it, and for most things, you'll be able to tell whether or not it's still good."

If you're not sure whether something has gone bad, it's probably best not to take any chances. The foods most prone to dangerous bacteria include meat, seafood, eggs and dairy products.