Best By vs. Use By vs. Sell By

"Sell by" is aimed at the store, not the shopper — it tells the retailer how long to display the product, so staff can rotate stock. It is not a use-it-or-lose-it date for the person buying it, even though it's printed right on the package they take home.

"Best by" (or "best if used by") is the manufacturer's estimate of peak quality — flavor, texture, freshness — not a safety cutoff. Most food is still perfectly fine to eat after this date; it may just not be at its absolute best.

"Use by" is the phrase closest to a genuine safety signal, and it's the only one of the three that's actually legally required anywhere — on infant formula specifically, where the FDA does mandate a "use by" date tied to nutrient content and safety. On everything else, manufacturers can and do use "use by" loosely, sometimes meaning the same thing as "best by."

None of this is standardized because, with that single infant-formula exception, US federal law doesn't require any date labeling at all, let alone specify what the wording has to mean. Manufacturers pick whichever phrase fits their own convention. The result is three labels that look equally official on the shelf but carry three different (and sometimes overlapping) meanings.

FDA and USDA/FSIS recommend manufacturers voluntarily converge on "Best if Used By" for quality and reserve "Use By" for the rarer cases where safety is genuinely time-limited — but that's guidance, not a mandate, and any federal rule is still years off (projected compliance no earlier than 1 January 2028). California's AB 660, in effect since 1 July 2026, is the first state to make that exact "Best if Used By" / "Use By" split legally required, and bans "sell by" on consumer packaging entirely. Worth knowing if you shop or sell across state lines, and a preview of where national labeling is likely heading.

None of these three dates tell you, with any real authority, whether the food in front of you is good to cook tonight. That's a judgment call — smell, look, texture — the same one you'd make with anything unlabeled. It's also the reason FridgeAI starts from a photo of your actual fridge rather than a tracked expiry date: the label is one weak signal among several, not the final word.