Dates printed on packaged food in the United States look like regulatory information, but with one narrow exception they are not. They are quality estimates written by the company that made the product.
Federal law leaves most dating to manufacturers
Apart from infant formula, federal law does not require a date label on food, and it does not prescribe how any date that appears must be calculated or worded.
Manufacturers set dates using their own shelf-life testing, which measures how long flavor, texture, color and aroma hold up under expected storage conditions. The endpoint is quality, not the point at which food becomes unsafe.
Because there is no single rule, the same category of product can carry a best-by date from one company, a use-by date from another and a packed-on code from a third.
The phrases mean different things
A sell-by date is a stock rotation instruction aimed at the store, telling staff when to pull the item so a reasonable amount of home storage life remains for the shopper.
Best-if-used-by speaks to peak quality, while use-by is generally the manufacturer's estimate of the last date of good condition. Federal agencies have encouraged standardizing on fewer phrases to reduce confusion.
None of these phrases is a legal deadline for consumers, and none of them triggers any obligation to discard food that has been stored properly and shows no sign of spoilage.
State rules add their own layer
Individual states impose their own requirements, most commonly on milk and other dairy, and a handful restrict the sale or donation of food past a printed date.
That patchwork is why a gallon of milk in one state carries a date noticeably further out than an identical product in a neighboring state, since the dating convention differs.
Retailers layer store policy on top of state rules, often pulling product earlier than required to protect the shopping experience and reduce complaints about quality.
Pathogen risk follows handling, not the calendar
The organisms that cause foodborne illness are governed by temperature, time and contamination rather than by a printed date. A mishandled product can be unsafe well before its date.
Conversely, a shelf-stable canned good stored cool and dry can remain safe long after its quality date, with texture and flavor declining gradually rather than falling off a cliff.
This is why food safety guidance from federal agencies emphasizes refrigeration temperature, separation of raw and ready-to-eat food, and cooking practices rather than date reading.
Markdown programs work off the same dates
Supermarkets use the printed date to drive automatic markdowns, discounting meat, bakery and dairy items as they approach the pull date rather than after it.
Recovery programs and food banks also use the dates operationally, sorting donations by remaining quality life so that products move through distribution before condition suffers.
The practical result for a shopper is that a date is a planning tool for the seller first. Reading it as a safety threshold both wastes edible food and creates false confidence in mishandled food.