Do Food Expiration Dates Actually Matter? What "Best By" Really Means

Product information in this article is based on publicly available nutrition labels, manufacturer disclosures, and peer-reviewed research.

You open the fridge, grab the eggs, and see the date. It passed last week. Into the trash they go. Sound familiar? You just threw away perfectly good food, and you are not alone. According to ReFED, Americans throw away roughly 3 billion pounds of food every year because of confusion over date labels.

Here is the thing most people do not realize: with one exception, no federal law requires food manufacturers to put dates on their products. Those dates are about quality, not safety. And understanding the difference could keep you from throwing away food you did not need to toss.

What “Best By,” “Sell By,” and “Use By” Actually Mean

The biggest source of confusion is that no standardized system exists. Different companies use different phrases, and none of them mean “this food will make you sick after this date.” The USDA’s Food Safety and Inspection Service breaks it down like this:

“Best if Used By/Before” tells you when a product will reach its best flavor or quality. It does not indicate safety. “Sell By” tells the store how long to display the product for sale. It serves as an inventory management date, not a safety date. “Use By” marks the last date recommended for peak quality. It also does not indicate safety.

The only product that federal law requires to carry an accurate expiration date is infant formula. Everything else is voluntary, set by the manufacturer, and primarily about quality.

Eggs: Safe Weeks After Purchase

Eggs rank among the most commonly wasted foods due to date confusion. The carton says “sell by” and people assume that means “throw away by.” It does not. According to the USDA (via University of Nebraska-Lincoln Extension), fresh shell eggs stay safe for three to five weeks after purchase when you store them in the refrigerator at 40 degrees F or below. The “sell by” date on the carton tells the store when to pull them from the shelf, not when you should toss them at home.

If you are ever unsure, try the float test. Place the egg in a bowl of water. If it sinks, it is fresh. If it floats, the air cell inside has expanded, which means the egg is older but not necessarily bad. Crack it open and check for off smells before deciding.

Milk: Often Good Past “Sell By”

Milk is another food people rush to dump the moment the date arrives. But pasteurized milk stored at 40 degrees F or below typically stays safe for three to seven days past the sell-by date, according to University of Georgia food safety specialist Carla Schwan. That sell-by date tells the store when to rotate stock. It does not set a safety deadline for you.

Your senses can help guide you, but they are not perfect. Sour smell, curdling, or off flavor all signal that milk has spoiled. If it smells and looks normal and you stored it properly, it is often still usable past the printed date. However, as the USDA notes, proper temperature and handling matter more than sensory checks alone.

Yogurt: Built-In Protection

Unopened yogurt generally lasts one to two weeks past the purchase date when refrigerated, according to the USDA FoodKeeper app (via Houston Methodist). Yogurt’s live active cultures help extend its shelf life compared to plain milk. That “best by” date marks a quality threshold, not a countdown to danger.

Honey: Extremely Long Shelf Life

If there is a date on your honey jar, it mostly reflects quality, not safety. Honey has an extraordinarily long shelf life. Its low moisture content, naturally acidic pH, and production of hydrogen peroxide make it inhospitable to bacteria. Archaeologists have found honey thousands of years old in Egyptian tombs that remained edible.

If your honey has crystallized, it has not spoiled. Crystallization happens naturally. Warm the jar gently in warm water and it will return to liquid.

Hard Cheese: Mold Does Not Mean the End

Finding mold on a block of cheddar does not mean you need to throw the whole thing away. For hard cheeses like cheddar, parmesan, and Swiss, the Mayo Clinic recommends cutting away at least one inch around and below the mold spot. The dense, low-moisture structure of hard cheese prevents mold from penetrating deep into the block. The rest remains safe to eat.

Soft cheese is the exception. Discard brie, feta, cream cheese, and other soft varieties if you find mold, because higher moisture content allows mold threads to spread throughout.

Deli Meat: The One to Actually Watch

Not everything past its date stays safe, and this is where the nuance matters. Deli meats carry a real risk that other foods do not: Listeria monocytogenes. Unlike most bacteria, Listeria can grow at refrigerator temperatures. The USDA recommends consuming opened deli meat within three to five days, regardless of the date on the package.

This risk is not theoretical. In 2024, a Listeria outbreak linked to deli meats caused 61 illnesses, 60 hospitalizations, and 10 deaths across 19 states, making it the largest listeriosis outbreak since 2011. Pregnant women, adults over 65, and immunocompromised individuals face the highest risk. This is the one category where the date matters, where proper storage is critical, and where “when in doubt, throw it out” genuinely applies.

The Golden Rule

For many foods in your fridge, the printed date reflects quality, not safety. The USDA’s guidance is straightforward: if food looks spoiled, smells off, or tastes abnormal, discard it. However, your senses are not a complete safety net. According to the USDA, you cannot see, smell, or taste harmful bacteria that may cause illness. Some pathogens, including Listeria, can grow without changing the appearance of food.

That is why storage conditions and time limits still matter. Keep your refrigerator at 40 degrees F or below. Store eggs and dairy in the coldest part of the fridge, not in the door. And for foods that carry higher risk, like deli meat, follow recommended storage timelines rather than relying only on your senses.

Why This Matters Beyond Your Kitchen

According to the USDA, roughly 30 to 40 percent of the food supply in the United States goes to waste. A significant portion of that waste comes from consumers throwing out food that remains perfectly safe to eat, driven by confusion over what date labels mean. Learning the difference between quality dates and safety dates is one of the simplest ways to reduce waste and save money.

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FAQ

Can you eat food after the “best by” date?

In most cases, yes. “Best by” indicates peak quality, not safety. The food may taste slightly different after that date, but it generally remains safe to eat if you stored it properly and it shows no signs of spoilage.

What is the only food required by federal law to carry an expiration date?

Infant formula. It must contain specific nutrient levels, and those nutrients can degrade over time. Federal law does not require any other food product to carry a date.

How long do eggs last after the sell-by date?

Eggs stay safe for three to five weeks after purchase when refrigerated at 40 degrees F or below, according to the USDA. The sell-by date will likely pass during that time, but the eggs remain safe.

Can mold on cheese make you sick?

For hard cheeses like cheddar and parmesan, you can safely cut away surface mold. Remove at least one inch around and below the mold. For soft cheeses like brie and feta, discard the entire product if mold appears.

Why does deli meat carry more risk than other refrigerated foods?

Deli meat can harbor Listeria monocytogenes, a bacteria that grows at refrigerator temperatures. The USDA recommends eating opened deli meat within three to five days. People who are pregnant, over 65, or immunocompromised face the highest risk.

Sources

USDA Food Safety and Inspection Service. “Food Product Dating.” fsis.usda.gov
USDA Food Safety and Inspection Service. “Food Safety Education Month: Preventing Cross-Contamination.” fsis.usda.gov
University of Nebraska-Lincoln Extension. “Cracking the Date Code on Egg Cartons.” food.unl.edu
Schwan C. “Best by vs. sell by: UGA food safety expert explains expiration dates.” University of Georgia College of Family and Consumer Sciences. February 14, 2025. fcs.uga.edu
McCallum K. “How Long Is Yogurt Good After Its Expiration Date?” Houston Methodist On Health. December 6, 2022. houstonmethodist.org
Geiling N. “The Science Behind Honey’s Eternal Shelf Life.” Smithsonian Magazine. August 22, 2013. smithsonianmag.com
Mayo Clinic. “Moldy cheese: Is it OK to eat?” mayoclinic.org
Centers for Disease Control and Prevention. “Investigation Update: Listeria Outbreak, Meats Sliced at Delis.” November 21, 2024. cdc.gov
FoodSafety.gov. “Cold Food Storage Chart.” foodsafety.gov
ReFED. “How Do Date Labels Contribute to Food Waste?” refed.org
U.S. Department of Agriculture. “Food Loss and Waste.” usda.gov

Do Food Expiration Dates Actually Matter? What “Best By” Really Means