Expiration dates

What they are and how they work

In 1968, treasure hunters discovered a Civil War-era steamboat at the bottom of the Missouri River. Among the items recovered were several, intact cans of food. Years later, scientists opened the cans to find perfectly edible peaches, oysters, and tomatoes. They remained unspoiled for more than a century.

So why do modern canned foods claim to expire in a matter of months?


Here's the truth

Food expiration dates have nothing to do with safety and are only loosely related to quality.

They’re the manufacturer’s best estimate of when the product is at its freshest or “peak quality.” Many foods will stay good to eat days, weeks, or even months after those dates, depending on the food type. Except for infant formula, dates are not an indicator of the product’s safety and are not required to do so by federal law. 


Understanding expiration dates


Best Before

“Best Before” dates refer to quality rather than food safety.

It’s the date before which the brand stands by its product (unless it’s opened or left out in warm temperatures). Foods with a “best before” date should be safe to eat after the date has passed, but they may no longer be at their very best quality. This is also true for “best by,” “best if used by,” “use by,” “enjoy by,” and other similar expressions.

The Nose Knows!

Use your eyes and your nose. For the most part, you can trust your senses to know when food has gone bad. 

Milk, yogurt, juice, sauces—they can all be subject to the sniff or taste test. Even meat that looks a little faded or gray is okay to eat. The products to be careful with are those that pregnant women need to avoid—like deli meats and unpasteurized dairy products—and anything with mold.


Sell By

You can ignore “Sell By” dates as they are meant for grocery store staff. 

Manufacturers build in quality so that if the food is sold by that date. You can still bring it home and have a good quality shelf-life for some time.

Spoiled foods will develop an unappealing odor, flavor, or texture due to naturally occurring spoilage bacteria. If a food has developed such spoilage characteristics, it should not be eaten. 


okay, so

How long will unopened food last?

5-7 days

Whole Milk
Fresh Salsa
Sliced Bread

7-10 days

Non-Fat Milk
Cottage Cheese

1-2 weeks

Sour Cream

2-3 weeks

Reduced Fat Cream Cheese
Neufchatel Cheese
Cream Cheese

3-4 weeks


1 month

Sliced Semi-Hard Cheese

1-2 months

Shredded Cheese
Semi-Hard Cheese (Swiss, cheddar)

2-4 months

Hard Cheese (parmesan, Romano, asiago)
Box of Cereal
Dry Pasta Noodle


just Push pause

Freezing food is one good way to extend its life beyond the date.

It’s like pushing the pause button on your food.  Almost anything can be frozen—meat, milk, cheese, eggs, bread, unused pasta sauce.


Want to learn more?

Check out these resources.