Best By, Use By, Sell By: What Food Date Labels Actually Mean

There is a specific kind of standoff that happens at about 6pm, in front of an open fridge, holding a tub of yogurt. The date on the lid was four days ago. The yogurt looks like yogurt. Smells like yogurt. And there is no information anywhere on that container that tells you which of those two facts you're supposed to believe.

So it goes in the bin, because throwing away yogurt is cheaper than being wrong about yogurt. That trade happens in a lot of kitchens every night, and almost all of it is unnecessary — not because people are being careless, but because the labels are genuinely, structurally confusing.

Here's what those dates actually are, what they aren't, and the handful of cases where the date really is the boss of you.

The thing nobody puts on the package

Start with the fact that reframes everything else: in the United States, with one exception, federal law does not require a date on food at all. Manufacturers put them there voluntarily. The dates are the company's own estimate of how long their product will still taste the way they want it to taste — a quality forecast, not a safety cliff.

The exception is infant formula, which is federally regulated and where the date is real. We'll come back to that, along with the other cases that deserve respect.

Everything else is a manufacturer saying: we tested this, and by roughly this date the texture starts to go, or the color dulls, or the crackers stop being crisp. That is useful information. It is not a countdown to food poisoning, and treating it as one is the single most expensive misunderstanding in the average kitchen.

The four phrases, decoded

“Best if Used By” / “Best Before”

The most common and the most misread. This is a pure quality date. The crackers will be less crisp. The canned soup will taste slightly flatter. Nothing about that date makes the food unsafe, and the food does not know the date has passed. Both the USDA and the FDA have pushed the industry toward standardizing on this phrasing precisely because it's the honest one for most products.

“Sell By”

This one isn't addressed to you at all. It's a stocking instruction for the store — the last day the retailer should display it, with a deliberate buffer built in so the food is still good for a reasonable window after you carry it home. Milk with a sell-by date of Tuesday is not milk that turns on Tuesday. Reading a sell-by date as your deadline means throwing away food during the exact window it was designed to be eaten in.

“Use By”

The one that sounds most like an order, and mostly isn't one. On the majority of shelf-stable and refrigerated products, “use by” is still the manufacturer's last date for peak quality. On infant formula it is a genuine safety and nutrition date. That two-meanings-one-phrase problem is why the label reform effort exists, and until it finishes, the phrase alone can't tell you which kind you're holding — the product category can.

“Freeze By” and the codes that aren't dates

“Freeze by” is a quality instruction: freeze it before this date and you keep the texture you paid for. And that string of digits stamped into the base of a can is usually a packing or lot code for the manufacturer's own traceability. It is not a message to you and shouldn't be read as one.

The four times the date wins

Being relaxed about labels is not the same as being relaxed about food safety. There are real cases where the printed date — or the packaging — overrules your senses, and they're worth knowing by heart:

• Infant formula. Non-negotiable. Past the date, nutrients degrade and the formula may no longer meet the nutritional profile on the label, regardless of how it looks.
• Ready-to-eat chilled foods— deli meats, soft cheeses, smoked fish, pre-made salads. The organisms of concern here can grow at refrigerator temperatures without ever producing a smell or a color change. Your nose is not a sensor for this category, and for anyone pregnant, elderly, very young, or immunocompromised, the printed date is the rule.
• Any damaged can.Bulging, leaking, deeply dented along a seam, or spurting when opened — that goes out unopened, whatever the date says. The date was never the risk.
• Anything that was left out.Two hours at room temperature (one if it's properly hot out) resets the clock on perishable food no matter how far away the printed date still is. Temperature history beats the label in both directions.

What actually determines whether food is still good

Once you drop the label as your primary signal, you need a real one. Food doesn't degrade on a calendar; it degrades according to how it's been treated. Four variables do almost all of the work: temperature, air, moisture, and time — roughly in that order of importance.

Which is why the highest-leverage thing in this entire article has nothing to do with reading labels: check that your fridge is actually at or below 40°F (4°C). A fridge running a few degrees warm shortens the life of everything inside it by days, and it does so invisibly. A fridge thermometer costs a few dollars and is worth more than any amount of date-label expertise.

Then, per category, the checks that actually work:

• Milk and yogurt.Smell first, then taste a small amount. Spoiled dairy announces itself unmistakably — this is the category where your senses are most reliable, and where the most food gets binned unnecessarily.
• Eggs.Float them in water. Lying flat on the bottom means fresh; standing on end means older but usually fine cooked through; floating means the air cell has grown large enough that it's time to let it go. Crack questionable ones into a separate bowl, never straight into the batter.
• Raw meat and fish. Trust smell and touch over color. Beef going brown in the middle of a package is oxygen, not spoilage. Slimy or tacky surfaces and any sour or ammonia note are the real signals, and this is the category to be most conservative in.
• Hard cheese.A spot of surface mold can be cut away with a generous inch-wide margin. Soft cheeses, yogurt, and anything with visible mold running through it are a different story — those go.
• Bread. Stale is a texture problem with obvious solutions (toast, croutons, breadcrumbs, panzanella). Visible mold means the whole loaf, not the good end.
• Dry goods and canned staples.Flour, rice, pasta, dried beans, and sealed cans routinely outlive their dates by a long way. The genuine failure mode here is rancid fats — nuts, whole-grain flours, and oils go off long before they look wrong, and rancidity is easy to smell once you know what you're smelling for.
• Condiments.The high-acid and high-salt ones — vinegar, soy sauce, mustard, hot sauce — are essentially designed to last. Mayonnaise and anything dairy- or egg-based is not in that group.

The freezer is a pause button, and almost nobody uses it

Freezing before the deadline is the move that makes all of the above academic. Freezing halts spoilage; it doesn't reverse it, so what you freeze is what you get back, which means the trick is freezing things while they're still good rather than as a last rite.

Bread, butter, hard cheese (fine for cooking after), most raw meat, cooked rice, stock, herbs in oil, tomato paste in tablespoon-sized blobs, ripe bananas for baking, milk if you leave headspace — all of these freeze well and take about ten seconds of forethought. The main casualties are texture-dependent items: lettuce, raw potatoes, cream sauces, and anything you plan to eat raw.

The label was written by someone who has never seen your fridge

That's the core of it. A printed date is a single number chosen months before purchase, for an average product, in an average fridge, on an average journey. It cannot know that your milk sat in a hot car for forty minutes, or that your fridge runs cold, or that you opened the sour cream on Sunday and it has been buried behind a jar of pickles ever since.

The thing that canknow all of that is a record of what you have and roughly when it arrived. That's the whole idea behind Custrd's Kitchen: when milk lands in your inventory it gets days, when potatoes land they get weeks, and every estimate stays editable — because the estimate is a starting point, not a verdict. Staples like salt and olive oil can be flagged as always on hand, so you never track them again.

More usefully, the dates aren't the point of the dates. Anything running short lands in a Use soonview, and the app starts suggesting real meals built around those exact ingredients. That's the difference between a reminder and a plan — “your cream is dying” changes nothing, while “here are two dinners tonight that use it” changes what you cook. It's the same mechanism we've written about at length in cooking through what you already own.

If you take one thing from this

Stop treating printed dates as instructions and start treating them as one input among several. Check your fridge temperature. Keep an “eat me first” bin at eye level. Freeze things while they're still good, not as a final gesture. Use your senses on the categories where they work, and defer to the label on the four where they don't.

And when you're holding three things that need using tonight and no idea what they add up to, the Custrd recipe finder will match them against the libraryand show you what actually works — recipes with real ingredient lists, real methods, and a photo of the finished dish. It runs in any browser, no signup.

The iOS app, Kitchen inventory and all, is out now — it's free on the App Store.