What Are the Facts Behind 'Sell By' Dates?

Egg Expiration Date

Story at-a-glance -

  • “Sell by” dates are there to help retailers ensure proper product turnover when stocking shelves; they’re not a measure of food safety
  • “Best by” or “best before” dates are set by the manufacturer to suggest when to consume the food by for best flavor or quality; they’re also not a measure of food safety
  • A “use by” date is the last date recommended for the use of the product while at peak quality; while it’s typically recommended to follow the “use by date,” many foods can be safely consumed even after they’re “expired”

By Dr. Mercola

Every year, people in the U.K. throw away more than 93 million gallons of milk, 733,000 tons of potatoes and 473,000 tons of bread, according to U.K. supermarket chain Sainsbury's.1 Similarly, the average U.S. family of four wastes more than 2 million calories, which equates to $1,500 worth of food, every year.2

Wilted or spoiled produce, moldy bread, or leftovers that sit too long in the fridge are common contributors to such food waste, but so are potentially good foods that get thrown away solely based on their "sell by" dates.

Labels like "use by" and "sell by" on foods aren't actually an indicator of food safety, as many believe them to be.

A report from the Natural Resources Defense Council (NRDC) and Harvard even found that more than 90 percent of Americans are throwing out food prematurely because of misunderstandings of what such dates actually mean.3

The researchers concluded that food dates generally lead to good food getting thrown away and may at the same time prompt you to eat a food that's actually spoiled because of "undue faith in date labels."

There Is No Universally Accepted System for Food Dating in the U.S.

More than 20 U.S. states require dating of some foods, but such labels vary significantly in different areas of the country. With the exception of infant formula, there is no uniform or universally accepted system used for food dating in the U.S., nor is there any federal requirement for food dates.

In other words, it's a veritable free for all. Food may be labeled with "open dating," which refers to use of a calendar date, or "closed" or "coded" dating, which refers to dates that are written in code for use by the manufacturer.

The latter may be used for shelf-stable products (cans, boxes, etc.) while open dating is typically found on perishable foods including meat, eggs and dairy products.

How to Decipher Food Product Dating Labels

There are other food-dating labels that you may see as well, and while many regard them as interchangeable, each actually has it's own unique meaning, as follows:

Sell By — Not Even Meant for Consumers

"Sell by" dates aren't meant for consumer use at all. They are there as tools to help retailers ensure proper product turnover when stocking shelves, yet many consumers believe it is a measure of food safety.

The dates lead to so much confusion and food waste that the NRDC report authors suggested making "sell by" dates invisible to consumers. That being said, the U.S. Department of Agriculture (USDA) states you should buy the product before the "Sell By" date expires.4

Best if Used By (or Before) — Not a Measure of Food Safety

This date is set by the manufacturer to suggest when to consume the food by for best flavor or quality. However, it is not a measure of safety and foods can typically be safely consumed after the "best by" or "best before" date, often with minimal, if any, changes in taste or texture.

Food manufacturers want you to consume their products at their peak freshness and flavor, which means many set food dates conservatively. The methods used by manufacturers to set food dates vary. NRDC explained:

"Some use lab tests, others use literature values, and yet others use product turnover rates or consumer taste testing …

In consumer testing, some manufacturers will allow for a level of change in quality over time before setting a date limit, whereas others set them more conservatively

… Thus, while open dating appears on the surface to be an objective exercise, consumer preferences and brand protection impact the way most of these dates are determined.

In most cases, consumers have no way of knowing how a "sell by" or "use by" date has been defined or calculated, and the method of calculation may vary widely by product type, manufacturer and geography."

Use By

A "use by" date is the last date recommended for the use of the product while at peak quality. This date is also determined by the manufacturer and may vary widely even between similar products.

The USDA recommends, "If a product has a "use by" date, follow that date." However, they also note:5

"Use by" dates usually refer to best quality and are not safety dates. Even if the date expires during home storage, a product should be safe, wholesome and of good quality if handled properly."

The exception is infant formula — the only food product with a federally regulated date label, as the nutrients in the formula may decline over time or the product may separate.

Federal regulations require that formula consumed by the "use by" date must contain the quantity of each nutrient listed on the label. It also must maintain quality so that it can pass through an ordinary bottle nipple without clogging. Infant formula should not be used after the "use by" date.6

Three-Digit Codes on Egg Cartons

Eggs with the USDA grade shield (such as Grade AA or Grade A) must display the pack date, which is the day the eggs were washed, graded and placed in the carton.

The pack date is a three-digit code that represents the consecutive day of the year (January 1 is 001 and December 31 is 365).

The "Sell by" date on the carton must be within 45 days of the pack date, although eggs are typically safe to use for three to five weeks after you purchase them.

If you're wondering if your eggs are still good, put them in a bowl of water. If they sink, they're fresh; if they float, they're not good to eat.

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Is It Safe to Eat Moldy Food?

Mold that's visible may appear to exist in contained areas on your food — a gray furry spot here or a few green dots there. However, beneath this visible mold are likely deep roots that may have invaded the rest of the food.

In cases where the mold is dangerous, its toxic elements may be contained not only in these threads but also throughout the food.

For this reason, if you see mold anywhere on a soft, easily penetrable food such as soft cheese, soft fruits and vegetables (tomatoes, peaches, cucumbers, etc.) and bread, you should discard it.

You may also need to toss nearby foods that may have touched the moldy area, as mold can spread quickly and easily, especially in produce. Moldy foods that you throw away should be put into a small paper or plastic bags so the mold cannot escape.

Do not attempt to sniff the moldy food to see if it's spoiled, as this can introduce mold spores into your respiratory tract. In the case of harder foods (hard cheese, cabbage, bell peppers, carrots, etc.), it's acceptable to cut off the moldy spot and about 1 inch around it (to ensure you've removed any roots).

When doing this, be sure the knife does not touch the mold and contaminate the area you are cutting. You can find more information about how to determine when a moldy food should be kept or discarded here.7

Can Thawed Meat Be Refrozen?

You've taken a roast out of the freezer, thawed it, then realized you're not going to be able to cook it when you planned. Can you safely put it back in the freezer or does this pose a safety risk? Go ahead and put it back in the freezer.

It's one of the most widely circulated myths that refreezing food is dangerous. While putting a thawed piece of steak or brick of cheese back into the freezer might lead to changes in taste or texture, it's perfectly safe and poses no risks to your health (provided it was thawed safely in the first place).

One of the greatest factors impacting whether your food is safe isn't whether it's been previously frozen but rather is related to how much time it spends in the temperature "danger zone" (between 40 and 120 degrees F).8 The worst way to thaw frozen food is to let it sit out on your kitchen counter. Thawing frozen meat, poultry or seafood by running warm water over it is also risky from a food-safety standpoint.

If you need to thaw meat or poultry quickly, you can run cold water over it or submerse it in cold water, changing the water every 30 minutes until it's thawed.9 If you use this latter method for thawing, it should be cooked immediately — not refrozen or put back in the fridge.

Freezing your food can be useful to help cut down on food waste. While I generally recommend consuming your food as fresh as possible, research suggests frozen foods may contain comparable nutrients as fresh foods and at times be even more nutritious.10 Most foods can be frozen successfully, provided you store them correctly in your freezer.

However, freezing does alter or degrade the quality of some items. Spices and seasonings are particularly vulnerable; sour cream, cabbage, celery, lettuce, radishes and sauces made with milk are other examples of foods that generally do not freeze well.11

Food Dates Were Created Because of Processed Foods

I recommend buying your food locally, preferably from a small organic farm you can visit and inspect for yourself. This guarantees that you get the freshest foods right from the start, giving you a few extra days of leeway before they spoil. It was only in the last few decades that food dates were even deemed necessary, and it coincided directly with an increase in processed foods — and a detachment of the consumer from where their food was grown. According to the NRDC report:12

"Expiration dates on food arose out of a concern for the food's freshness, not its safety. As Americans moved off farms over the 20th century and grew more distant from their source of food, they began losing the ability to tell how fresh their food was.

This was partly because they were purchasing it in a store and didn't know its history, and partly because the knowledge of how to store and handle fresh food was progressively lost as processed foods became prevalent. Forced to trust manufacturers and grocery stores to supply them with fresh food, consumers began demanding verification of its freshness."

The best solution, for your health and also for clarity on how old your food actually is, is to return to the traditional practice of buying most of your food fresh from the farm or farmer's market.