What date labels on food actually mean
The date stamped on a package of food in an American grocery store is, with narrow exceptions, neither a legal requirement nor a safety instruction. It is the manufacturer's estimate of how long the product will taste the way the manufacturer intends. Most people read it as a deadline, and throw out food that is fine.
Nearly all of it is voluntary
The Congressional Research Service reviewed the law in its briefing Uniform Date Labeling of Food May Address Food Waste, updated in September 2023. Its summary: except for infant formula, federal law does not require the food safety agencies to implement a national food dating system. The statutes governing the Food and Drug Administration and the Department of Agriculture do not give either agency explicit authority to impose date labeling requirements. The decision belongs to the manufacturer.
Two narrow federal rules survive that. The Food Safety and Inspection Service, which regulates meat, poultry and eggs, requires a pack date on poultry products, meaning the date the product was packaged. And a date that does appear on a meat or poultry label has a prescribed form: 9 CFR 381.129(c) and its counterpart for meat require the month and the day of the month on every product, the year as well on products hermetically sealed in metal or glass, dried or frozen, and immediately next to the date a phrase explaining what it means. A dated tray of fresh chicken therefore needs no year; a dated can does. The label is optional; being clear about it, once you print it, is not.
State law fills the gap unevenly. CRS reports that 41 states and the District of Columbia require date labels on some foods, while nine states require them on none. Where states do regulate, the rules conflict with the food industry's own voluntary standard often enough to matter: 27 states have at least one product where the two disagree, most commonly shellfish, eggs, and milk and dairy.
The result is what you see in the aisle. The Food Marketing Institute counts more than ten different explanatory phrases in use, including sell by, use by, best by, fresh until, use or freeze by, enjoy before, and expires on.
What each phrase means
Sell by
A date for the store, not for you. CRS defines it as the date by which the retailer should sell the product, and notes that roughly one-third of the product's shelf life typically remains after it for use at home. Buying something on its sell by date is not buying something that has gone off.
Use by
The date the manufacturer picked as the one by which the product should be consumed. The University of Maine Cooperative Extension describes it as the last date recommended for peak quality, and says it does not indicate food safety except on infant formula. The narrow exception CRS names is reduced-oxygen packaging, where certain retail packs are required to carry a use by date and a refrigerated shelf-life limit.
Best if used by, best before
The clearest of the phrases, because it says what it is doing. UMaine Extension puts it as a recommendation for best flavor and quality, and not an indication of food safety. CRS records that FDA has expressed general support for the food industry's own efforts to standardize labeling terms, without having the authority to require it.
Freeze by
When to move it to the freezer to hold quality, not when to throw it away. CRS notes that freeze by statements are increasingly paired with a best if used by date on poultry and fish, in the form of a shelf date plus a number of days once it comes out of the freezer.
Anything reading as an expiration
Some manufacturers print a phrase that sounds absolute. UConn Extension's guidance is to treat a true expiration date as the one date to respect and to read the rest as quality dates, since food past a sell by or best by date is generally safe though it may have deteriorated in flavor, texture or appearance.
Infant formula is the one real exception
CRS and UMaine Extension both carve out the same exception, and an FDA rule is the reason. 21 CFR 107.20 requires the label of an infant formula to bear a use by date, with the month and year chosen on the basis of tests or other information showing that, until that date and if the formula is handled and prepared as the label directs, it will still contain no less than the quantity of each nutrient listed on its label and be of acceptable quality. That is a guarantee about the contents of the can rather than a prediction about flavor, which is why UMaine Extension, having called use by dates a quality measure and not a safety one, makes formula the exception to its own rule. It is the one aisle where the printed date is an instruction rather than an opinion, and it should be treated as one.
What the confusion costs
CRS cites a USDA estimate that 30 to 40 percent of the food produced in the United States goes unsold and uneaten. It puts the share attributable to date-label confusion specifically at about 7 percent of all US food waste, and reports research finding that more than 80 percent of consumers discard food near the package date at least occasionally.
Estimates of that share vary, and larger ones circulate. Seven percent is the figure the congressional briefing settled on. It is still a great deal of food thrown out on the strength of a misread word.
How to judge food when the date will not
Both extension services give the same method, which is older than the labels.
Look at it. Color changes, surface moisture where there should be none, mold, a swollen or leaking package. Smell it. Sour where it should be neutral, or the flat cardboard smell of oxidized fat in nuts and oils. UConn's phrasing is to use your eyes and nose regardless of the date on the package.
Then apply the storage history, which the label knows nothing about. A date assumes the product was kept at the temperature it was designed for and never opened. A gallon of milk that spent forty minutes in a warm car has a shorter real life than its printed date, and an unopened jar in a cool cupboard often has a longer one. The date is a prediction made before the food met your kitchen.
Where the two disagree, UMaine Extension's rule for the perishable categories is that doubt settles it: fresh meat, poultry and fish are not worth a coin flip.
For a can of beans, a box of pasta, a jar of peanut butter or a bag of rice, the date is a note about flavor, and the package is telling you nothing you cannot find out by opening it.
The date is one input
A printed date is a manufacturer's forecast about a package that had not yet been bought, driven home, opened halfway, and pushed to the back of a shelf. It is worth reading and it is not the answer on its own. What the food looks like, what it smells like, and how long it has actually been in your house are the other three inputs, and the last one is the only one nobody writes down.
Sources
- Congressional Research Service, Uniform Date Labeling of Food May Address Food Waste, IF10398, updated 15 September 2023
- University of Maine Cooperative Extension, Understanding Food Product Dating Labels, February 2025
- UConn Extension, Expiration, Use-By and Sell-By dates: What do they really mean?
- 9 CFR 381.129(c), calendar dates on poultry product labels, 2024 CFR annual edition
- 21 CFR 107.20, directions for use on infant formula labels, 2024 CFR annual edition
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