Walk down any grocery aisle and you will see a date on nearly every package. Sell by, best by, use by, best if used by, enjoy by, freshest before. The wording changes from brand to brand and the placement moves around the label, but the impression is the same. It reads like a rule someone is enforcing. Federal law requires a date on exactly one food product sold in the United States, and it is not milk, meat, eggs, bread, or canned soup. It is infant formula.
The Food and Drug Administration requires a use by date on infant formula, and the reason is nutrition rather than spoilage. Formula is often the only thing a baby eats, so the label has to guarantee that the product still contains each nutrient in the amount printed on the can. Past that date the formula may separate or the vitamin content may drop below what the label claims. That is a measurable standard a regulator can enforce, which is why a federal rule exists for it. The Department of Agriculture, which oversees meat, poultry, and processed egg products, does not require quality or safety dates on the foods under its watch. Its own guidance says so in plain language.
Everything else you see is voluntary. A company decides how long its product tastes the way it wants the product to taste, prints a date based on that, and moves on. Some brands run shelf life studies. Some copy an industry norm. Some set the window short on purpose because faster turnover keeps the product on shelves fresher and keeps stores reordering. A few states layer their own rules on top for milk or shellfish, which is why the same gallon can carry different dates in different places. There is no national standard behind the number, and no agency is checking it.
The words themselves carry different meanings, and most shoppers have them backward. Sell by is a message to the store, not to you, telling the stock clerk when to pull the item and rotate the shelf. A carton of milk with a sell by date is usually good for a stretch past it if it stayed cold. Best if used by speaks to peak quality, meaning flavor and texture, not safety. Use by is the only phrase that leans toward a safety deadline, and outside of infant formula even that one is a manufacturer's call. Federal guidance now encourages companies to standardize on best if used by, precisely because so many people read every date as a hard stop.
That confusion has a price, and it lands on households. Studies of American food waste consistently find that a large share of what gets thrown out at home is discarded on the strength of a date, not on smell, look, or taste. A family tossing a yogurt on the printed day is throwing away money for no reason a food scientist would recognize. Grocery stores do the same at scale, pulling product that is still fine because a code date passed. Congressional researchers have looked at uniform date labeling for years as a way to cut that waste. Bills to standardize the wording have been introduced repeatedly without passing.
None of this means dates are useless or that spoilage is imaginary. Some products really do degrade in ways worth respecting. Cold cuts and soft cheeses can support listeria growth over time. Ground meat spoils faster than a whole cut because grinding exposes more surface, and oils go rancid on a schedule you can taste. Anything that has been left out of refrigeration for hours is a different question entirely, and no printed date accounts for that. The date on the package assumes the product was handled correctly the whole way, which is exactly the assumption a shopper cannot verify.
What actually protects you is storage and your own senses. Temperature does more work than any label, and a refrigerator running at or below 40 degrees keeps food safe far longer than one that drifts warm. Sealed packages last longer than opened ones, and the clock effectively restarts once you break the seal. Freezing stops the quality clock almost entirely, which is why a date on a frozen item tells you about texture rather than risk. Smell and appearance catch most real spoilage. When something looks wrong, smells sour, or has changed texture, that beats any number printed weeks earlier by a marketing team.
The useful shift is to read the date as information rather than instruction. Look at the wording first, because sell by and best if used by are telling you about a store shelf and a flavor target. Check how the item was stored, since that matters more than the number. Buy what you will actually eat in the window you will actually eat it. Use the date to plan the order you cook things in rather than as a trigger for the trash can. The one date on the shelf that a federal agency stands behind is on a can of formula, and every other one is a company telling you when it thinks its product stops being at its best.
Sources: USDA Food Safety and Inspection Service, Food Product Dating; Congressional Research Service, Uniform Date Labeling of Food May Address Food Waste.
