Expiration Date

What Is an Expiration Date?

An expiration date is the last day that a consumable product such as food or medicine will be at its best quality, according to the manufacturer. There are important differences between expiration dates on food and those on medicine:

  • Expiration dates on food products are not required by federal law, except for infant formula. When they're used, they usually indicate that the food should have its best taste and texture up until that date. It is an assurance of quality, not an assurance of safety.
  • Expiration dates on prescription and over-the-counter drugs are mandated by federal law. The dates indicate the period during which the product is guaranteed to be safe and effective based on the manufacturer's internal testing.

Key Takeaways

  • Expiration dates on food are not required by federal law except on infant formula.
  • Dates on food indicate how long they will retain their freshness and best quality.
  • Most perishable foods are good well beyond the "sell by" or "use by" date.
  • Prescription and non-description drugs must carry expiration dates by federal law. 
  • Prescription drug expiration dates indicate how long the manufacturer can guarantee the product's safety and effectiveness based on its own internal testing.


Understanding an Expiration Date

A product may have a "sell by" date, a "use by" date, a "best by" date, or a "do not use after" date stamped on the package or the container. They all have different meanings but only the "do not use after" date is a warning that the product should be discarded at that date because it may be unsafe, ineffective, or both.

The sell-by date is meant to tell store clerks when to remove the product from the store's shelves. The use-by date tells consumers when the product's quality may have deteriorated. The best by date merely suggests that the product's taste or texture may deteriorate after that date.

Federal law does not require food producers to provide any of these dates on food, with the sole exception of infant formula. Nor does the U.S. Department of Agriculture (USDA) provide much guidance on the proper date labeling of food, except for that sole exception of infant formula.

In fact, the USDA notes that about 30% of the American food supply is "lost or wasted," in part because many consumers toss out food that is still wholesome. It suggests that a smell test or a taste test are more accurate indicators of edibility than a label.

Controversy Over Food Expiration Dates

Expiration date stamps on food began to emerge in the 1970s when consumer advocates complained about the lack of assurances that packaged foods were still safe and edible at the time they were purchased. More recently, there have been complaints that the date stamps are intentionally inaccurate to persuade buyers to toss out and replace products that are still good to eat.

Many states have adopted their own requirements, so food producers now routinely mark their products regardless of their destinations.

So, expiration dates on food can be ambiguous. But expiration dates on medicine are straightforward.

Why Using Expired Medications Can Be Risky

Federal regulations require prescription medicines to be date-stamped.

Over-the-counter medicines like aspirin, cough syrup, and herbal products have an expiration date, often abbreviated EXP followed by a month and year. This indicates the date after which the manufacturer does not guarantee the potency or effectiveness of the product.

In most cases, this indicates the length of time that the manufacturer is certain that the drug is safe and stable, based on its own product testing. That is, the manufacturer does not accept liability for the product beyond that date.

In fact, the manufacturer accepts liability for the product only until the package is opened, not until its contents are used up..

Expiration Date Mandate

Food tends to look, smell, or taste bad when it's no longer edible. However, the expiration date is the only indication that a prescription drug is still safe and effective.

In the late 1970s, the U.S. Food and Drug Administration (FDA) mandated that all prescription and over-the-counter (OTC) medical products be marked with an expiration date. Expiration dates for medicines are often marked EXP and may be printed on the label, stamped onto the packaging, or both.

Even small amounts of certain medications can be fatal to children or pets. They should be disposed of once they pass their expiration dates.

It is especially important to adhere to the expiration dates of pharmaceuticals because their chemical composition can change over time, making them less potent, ineffective, or even harmful.

In some cases, the FDA may extend the expiration date of a drug if there is a shortage of it. The extended expiration date is based on stability data for the medication that has been reviewed by the FDA.

Discarding Expired Medications

Dumping expired medications in the trash is not a good idea. There may be disposal instructions on the drug's packaging. You also can check for drug take-back programs in your state or municipality.

In the absence of specific instructions or take-back programs, U.S. federal guidelines recommend disposing of expired or unwanted medicines by putting them in a bag or container and mixing them with coffee grounds or kitty litter. Some medications can be flushed.

Expiration Dates for Food

Expiration dates on food are a different story. Food manufacturers date their products to notify store clerks or consumers, or both when the product may no longer be at its best quality. Infant formula is the only food product that must carry a true expiration date under federal law.

  • Open dating is a calendar date marked on a food product by the manufacturer or retailer. It is intended to indicate the last date at which the product is guaranteed to be at its best in terms of quality.
  • Closed dating is a code, unreadable to most consumers, that consists of letters and/or numbers. Manufacturers apply them to record the date and time that the item was processed.

The FSIS: Watchdog for Meat, Poultry, and Eggs

The Food Safety and Inspection Service (FSIS), an agency of the USDA, is the public health regulatory agency responsible for ensuring that America's supply of meat, poultry, and eggs is safe, wholesome, and correctly labeled and packaged. 

Manufacturers are not required to mark their products with expiration dates, but if they do the labels must be truthful and not misleading. A calendar date must indicate both the month and day of the month. Shelf-stable and frozen products also must display the year. In any case, the date must be explained with a phrase such as "best if used by."

WebMD notes that eggs, for example, are good for three to five weeks after their sell-by date.

Date-Labeling Phrases for Food Products

There are no uniform or universally accepted descriptions used on food labels for open dating in the United States. Producers use a variety of phrases on their labels to describe quality dates: 

  • Best if used by/before: This indicates the date after which the product may no longer retain its best flavor or quality.
  • Sell-by: A sell-by date indicates when the product should be removed from store shelves. It is used primarily on refrigerated products. The product is still good for some time after that date.
  • Use-by: This is the last date on which the product will be at its peak quality. It is not a safety date except when used on infant formula.
  • Freeze-by: This date indicates the last day on which a product should be frozen to maintain its best quality.
  • Expires on/Do not use after: These are the only true expiration dates of the bunch, indicating that the product may be ineffective after that date. In addition to baby formula, products like cake mix and baking powder may carry this warning.

How Food Manufacturers Decide Quality Dates

When determining the date by which a product will be of the best quality, producers and retailers consider factors like the length of time and the temperature at which a food is stored while it's in transit and while it's being offered for sale.

Other factors, such as the particular characteristics of the food, and its type of packaging will affect how long a product will be of optimum quality.

Food Safety Tips

The date on perishable food is a good indicator of how long it has been sitting around in a warehouse or on the store shelves. It also suggests that the product may (or may not) be at its best after the date on the label.

Nevertheless, these products still have some shelf life left in them if they're stored and handled properly.

A wise consumer will look, smell, taste, or touch food to check whether it shows any signs of spoilage before throwing it out.

The USDA maintains a food storage safety chart listing foods from sauerkraut to egg whites.


Expiration Dates for Prescription Drug Patents

For prescription drugs, expiration dates have another unrelated meaning.

The U.S. Patent and Trademark Office awards medical patents to pharmaceutical companies when a new brand-name drug is released to the market. The patent protects the drugmaker from having its drug copied by competitors for a certain time, typically 20 years.

The patent exclusivity for orphan drugs lasts for seven years. A patent for a new chemical lasts for five years.

The Orange Book—a list of drugs that the FDA has approved as both safe and effective—cites the patents for new drugs, along with their expiration dates.

Under the Hatch-Waxman Act, for a generic drug manufacturer to win approval for a drug, the manufacturer must certify that it will not launch its generic product until after the original drug's patent has expired unless the patent is found to be invalid or unenforceable or the generic product will not infringe upon the listed patent.

Is It Okay to Use Some Medicines After Their Expiration Dates?

It is a bad idea to use any medicine after its expiration date. It is no longer guaranteed to be safe or effective, according to the Food & Drug Administration (FDA).

For that matter, the FDA warns that medicines should be stored properly to remain good until their expiration dates. If they don't need to be refrigerated, store them in a cool dry place (not the bathroom cabinet).

How Long Can You Eat Food Past Its Expiration Date?

Here's some advice from the U.S. Department of Agriculture:

  • Canned goods will last for years if they're not opened and the can isn't damaged, no matter what the "best by" date is.
  • Packaged foods like cereal and pasta are safe well past any "best by" date, but may eventually acquire a stale or "off" taste.
  • Meat will keep for months in the freezer, but may eventually lose some of its flavor. It will not be unsafe. Bacteria don't grow in freezers.

The USDA also has a chart indicating the shelf life of many food products.

Can You Eat Expired Food If It Hasn't Been Opened?

The "use by," "sell by," and "best by" stamps all suggest an end date for the product in its unopened state. Most products are good for some time after the dates marked on the package if the package remains unopened. Whether it's opened or sealed, look at it, sniff it, or taste it before you throw it out.

In general, nonperishable foods like canned goods, pasta, and rice have a long shelf life and are good well past any expiration dates marked on them. Meat, dairy, and eggs are perishable, but a sniff test is more reliable than a sell-by date.


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