Food Expiration Dates: What do they really mean?

Are you one of those people who pour the milk down the drain on the expiration date?

Expiration dates on food products can protect consumer health, but those dates are really more about quality than safety, and if not properly understood, they can also encourage consumers to discard food that is perfectly safe to eat.

A recent poll of more than 2,000 adults showed that most of us discard food we believe is unsafe to eat, which is a good thing, of course, but it is important that we understand what food expiration dates mean before we dump our food — and our money — down the drain or into the garbage.

Which five foods are most often feared as being unsafe after the printed date? According to, we are most wary of milk, cottage cheese, mayonnaise, yogurt, and eggs, and offers these helpful explanations:

  • Milk: If properly refrigerated, milk will remain safe, nutritious, and tasty for about a week after the sell-by date and will probably be safe to drink longer than that, though there’s a decline in nutritional value and taste.
  • Cottage cheese: Pasteurized cottage cheese lasts for 10-14 days after the date on the carton.
  • Mayonnaise: Unopened, refrigerated Kraft mayonnaise can be kept for 30 days after its expiration date or 3-4 months after opening, the company told ShelfLifeAdvice.
  • Yogurt: Yogurt will remain good 7-10 days after its sell-by date.
  • Eggs: Properly refrigerated eggs should last at least 3-5 weeks after the sell-by date, according to Professor Joe Regenstein, a food scientist at Cornell University. Note: Use of either a sell-by or expiration (EXP) date is not Federally required, but may be state required, as defined by the egg laws in the state where the eggs are marketed.

The “Use-By” Date
The “use-by” or “best if used-by” date indicates the last day that the item is at its best quality as far as taste, texture, appearance, odor, and nutritional value. The decline after that is gradual. The use-by date refers to product that has not yet been opened.

The “Sell By” Date
The “sell by” date is not really a matter of food safety, but a notice to stores that the product should be taken off the shelf because it will begin to decline in quality after that date.

The Law
From the U.S. Department of Agriculture (USDA): “Product dating is not generally required by Federal regulations. However, if a calendar date is used, it must express both the month and day of the month (and the year, in the case of shelf-stable and frozen products). If a calendar date is shown, immediately adjacent to the date must be a phrase explaining the meaning of that date such as “sell-by” or “use before.”

There is no uniform or universally accepted system used for food dating in the United States. Although dating of some foods is required by more than 20 states, there are areas of the country where much of the food supply has some type of open date and other areas where almost no food is dated.”

Food-Borne Illness
Cross-contamination and unsanitary conditions are a primary cause of food-related illnesses, whether it occurs in the home or in a restaurant, and independent of any expiration date. The leading culprits:

  • Improper hand-washing prior to food preparation
  • Storing food at the wrong temperature
  • Cooking food to an inadequate temperature
  • Cross-contamination (raw meats that come into contact with salads, for instance)
  • Improper washing of fresh produce

The Yuck Factor: Common Sense Approach to Food Safety
Aside from any expiration date or lack thereof, if it is moldy or if it smells and looks spoiled, err on the side of caution. If it makes you say, “yuck,” throw it away.

Photo used under Creative Commons License via Flickr with thanks to goldeneel


Jo S.
Jo S2 years ago

Thank you Ann.

Joe R.
Joe R5 years ago

Very interesting.

Maria S.
Maria S6 years ago

I always check the expiration dates on everything I buy. If I have had something for longer than expected and close to the expiration date then I cook it or make it into something else. Like today I just finished making cookies and pudding with milk and yogurt that had tomorrows date to expire. I never throw out food. It is disrespectful when billions are suffering of hunger.

Ira M.
Ira M7 years ago

Good to know, thanks

Annemarie W.
Annemarie L7 years ago

Helpful! Thanks!

Mariles A.
Mariles A.7 years ago

very helpful, thank you so much. does this apply also to medicines? by the way, please remove the travian, with the arrow, it is very annoying to the eyes. instead of enjoying the articles, I am bothered by the glare and have lost interest in reading just to avoid the "lightning".

Vivianne Mosca-Clark

Thank you for th3 information. I use my nose when I check food. And it has worked for me.

Jennifer Davidson

Generally will keep a product a couple of days after the expiration/use by date. How long depends on the product. But I always use my nose and eyes first. 'If in doubt, throw it out.' I'd rather waste some food and money than risk mine and my families health with something that might be bad.

Carole K.
Carole K7 years ago

NOT automatic discard date! Rely & trust your own senses, judgment, & power of observation. Sounding like my mother & grandmother now: "Throwing out perfectly good food when millions of people in the world are starving is horribly wasteful!"

HELLO! Food you throw away causes you to BUY MORE!
More profits for food giants! Bottom line.....

Laura Thomas
Laura Thomas7 years ago

I never throw out food. It is disrespectful when billions are suffering of hunger. I buy small quantities that I can easily manage.