Sell-By, Use-By and Best-By: What Each Date Legally Means

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The "sell-by" date on a package of meat isn't the "use by" cutoff for cooking, and the "best if used by" warning on bread doesn't mean it's immediately unsafe. Food-date labels often fall into three categories: quality guides, safety cutoffs, or a mix of both. And a nationwide federal law doesn't dictate it all. Instead, food manufacturers set most expiry dates based on expected quality, while some states, such as Pennsylvania and California, restrict sales of date-past items. Items like milk and infant formula have the strictest safety rules.

The Main Terms

Under federal U.S. guidance, manufacturers typically use "Best If Used By (or Before)" to mark when a product loses its ideal flavor or quality, with usage still generally considered safe after. Manufacturers have determined that the product may be usable beyond the Sell-By date before quality declines below the manufacturer’s standard.

What Food Labels Mean in Practice

In practice, "Sell-By" guides a retailer’s inventory and isn’t a universal safety cutoff for consumers, as the FDA and USDA state. Instead, these dates may tell you the last expected date of peak quality if the product is refrigerated or frozen. If a product is refrigerated and is past the "use-by" date, it is still likely safe to use, but its quality may be reduced, per USDA's FAQ on expiration date extensions.

For instance, if deli meat has passed the "use-by" date, it's not safe to consume at typical refrigerator temperatures. However, the refrigerator may still prevent O157:H7 from multiplying if left buffet-style instead of refrigerator.

Otherwise, defrosting these foods ahead of use gets them into the "danger zone" (40-140 F) for some time, where pathogens may have a breeding ground.

Notably, clarifying that it's up to each company's side. When you put it all together, this creates some misalignment between food date labels and food safety.

Where State Law Steps In

Beyond the federal baseline, states like California and Pennsylvania add regulations over food-date labels. For example, a California 2026 law introduces clearer date label categories: "BEST if Used by" for quality, and "USE by" for food that may be unsafe after the date. Pennsylvania is strictest on milk: provincial statutes set 17-day maximum dating for pasteurized milk, and once the date is over: once a milk container passes the date, stores are legally barred from selling it. No fresh milk over 17 days.

Edible milk after the date window? Maybe or maybe not: the FDA suggests storage temperature gets the last word., putting 17-day state rules near the safety edge, and so the state regulations may create more waste than pathogens

Inside the Fridge: Shelf-Date vs. Refridgeration-Date

When a product passes its "sell by" or "use by" date, it's not always a universal safety cut-off. In many cases, quality is, as the name suggests, a qualitative judgment. Storing any date label near or beyond its date has a few practical considerations.

Refrigeration matters. Instructions may say an item is "best by" or "use by" a point, but that assumes you've stored it in a refrigerator at 4.4°C (40°F).

Consider the product. Different foods degrade at different rates. Generally, eggs have a longer latency than milk regardless of its label date and quality changes. However, a few foods follow a strict use by date: baby food, infant formula, dishes labeled as a "hot holding" food, and anything from a suitable refrigerator.

Determine the food code. Your state might add its own rules. Those extra regulations can change your shelf date into a safety expiration.

Foods Still Require Caution

While many "family" products preserve longer than their labels, some foods still require date labeling as an actual safety cutoff. One exception is infant formula. Federal law mandates manufacturers to submit a requirement to the FDA for dates at which the food will not be edible, ensuring formula still supports infants. Chalk it up to an old law. Government policy insists formula expire: formula dates are strict—it's not just marketing.

Another exception is reduced-oxygen packaging (ROP), like deli sliced meats, vacuum-sealed foods, and sous vide food. Within ROP, pathogens thrive without oxygen, so "use-by" dates are crucial on these packages, according to Congress.gov. Again, it’s a “food-safe” date for safety. Otherwise, the leftover party scene brings different rules. Leftovers require proper refrigeration.

Additionally, dishware marked as a "hot-holding" food needs special storage conditions to remain safe; your grandmother had this right and now the FDA agrees, especially when it comes to meat.

Why Food Labeling Matters

While most packaging should read "Use By" as its end date, it doesn't mean it might make you ill to consume milk another day at 40°F (4.4°C). Date labels matter, but federalized date labels aren't your sole authority to discard.