The short answer to the question most people bring to their kitchen shelf: with one exception, the dates printed on food packages tell you when a product is at its best, not when it becomes dangerous. That exception is infant formula, the only food category where federal law requires a date tied to nutrient content and safety. For everything else, safety depends on how the food was handled and stored — and on whether it shows signs of spoilage, according to the USDA's Food Safety and Inspection Service.
Beyond the Date: Understanding Food Quality vs. Safety
Walk down any grocery aisle and you'll see the familiar small print: "Best if Used By," "Sell By," a stamped date. Most shoppers read these as expiration deadlines and toss perfectly good food. The USDA's guidance flips that assumption. "Manufacturers provide dating to help consumers and retailers decide when food is of best quality," the agency explains, adding that "except for infant formula, dates are not an indicator of the product's safety and are not required by Federal law."
That distinction matters for both health and household budgets. Food waste driven by misunderstood labels is a real cost, and the USDA frames its dating guidance partly as a food-waste issue. The agency also notes that factors like how long and at what temperature a food was held during distribution, the food's own characteristics, and its packaging all affect how long it stays at optimum quality — which is why a date on one brand's product may differ from a nearly identical one beside it.
The Critical Exception: Infant Formula's True Expiration Date
Infant formula stands alone. It is, as a Midwest Food Bank guide by Gergely Bata puts it, "one of the few food products in the United States that requires a federally regulated expiration date." The reason is nutritional rather than purely spoilage-based: after that date, nutrients in the formula may begin to break down, which can affect a baby's nutrition and development.
That makes the "Use-By" date on formula a strict deadline in a way that no other food date is. A caregiver who feeds formula past its date isn't just serving a slightly stale product — they may be serving one that no longer delivers the nutrient levels specified on the label. The practical rule is simple: if the date on infant formula has passed, discard it, even if it looks and smells fine. This article covers U.S. federal rules; state and local laws may add their own requirements.
Decoding Date Labels: 'Best By,' 'Sell By,' and 'Use By'
Once formula is off the table, the label vocabulary becomes easier to read correctly. "Best if Used By" or "Best By" indicates best flavor or quality — it is not a safety date, as the USDA states and as food-waste educators repeat. "Sell By" tells stores how long to display a product for inventory management. Even "Use-By" on ordinary foods, in most cases, reflects the manufacturer's estimate of peak quality rather than a hard safety line.
One label deserves caution. A shelf-life guide from Foodshare, a food-bank network, defines "Exp." or "Expires" as "a true expiration date. The food is not safe to eat and must be thrown away." That's a stricter reading than the USDA applies to quality dates generally, and it reflects how inconsistently labels are standardized. The safest interpretation: treat "Expires" language seriously, treat "Best By" as advisory, and never assume any label substitutes for your own inspection.
Your Real Guide to Food Safety: Proper Handling and Storage
If dates don't determine safety, what does? Handling. The USDA is blunt about the consequences of getting this wrong: if foods are mishandled, before or after the date on the package, bacteria — "including pathogenic bacteria that can cause foodborne illness" — can quickly multiply. The agency's example is a cold chicken salad taken to a picnic and left out above 40 degrees F (4.4 degrees C) for more than two hours, or more than one hour at 90 degrees F (32.2 degrees C) or above. That product should not be consumed, date or no date.
The American Heart Association echoes the same principles: food requiring refrigeration that sits out for hours at a picnic may be unsafe even if the date hasn't passed. Its handling guidance includes buying products before the date expires, taking perishables home immediately, refrigerating promptly, and freezing what you can't use within recommended times. The USDA adds that improperly defrosted meat and poultry, and handling by people who don't practice good sanitation, are common mishandling paths — so follow the preparation instructions on the label.
Spotting Spoilage: Observable Signs That Mean 'Discard'
Spoilage is the true indicator that food has become unsafe, and it announces itself through your senses. The Midwest Food Bank guide lists what experts generally recommend checking: smell, texture, mold, color changes, and storage conditions. Foods stored properly tend to last longer, so a well-refrigerated item past its "Best By" date may be entirely wholesome, while a mishandled one well within its date may not be.
Use those checks in order of obviousness: visible mold, sour or off odors, and slimy or altered textures are discard signals. When a food passes those checks and you know it was kept at proper temperatures, the printed date alone is not a reason to throw it away. This is general consumer guidance, not a substitute for advice from a medical professional or food safety expert about specific health situations.
Your Food Safety Decision Framework
This matrix walks through the sequence of checks in order: identify the food type, interpret the label, verify handling, then inspect for spoilage. Follow it top to bottom for any item in your kitchen.
| Step | Check | If yes | If no |
|---|---|---|---|
| 1 | Is it infant formula? | Discard if the "Use-By" date has passed — nutrients may have degraded; do not feed even if it appears fine | Go to step 2 |
| 2 | Does the label say "Expires" or "Exp."? | Treat as a true expiration date and throw it away, per Foodshare's shelf-life guidance | Go to step 3 |
| 3 | Was it handled and stored properly — refrigerated promptly, kept below 40 degrees F, not left out over two hours (one hour above 90 degrees F), defrosted safely? | Go to step 4 | Discard — mishandled food can harbor multiplying pathogenic bacteria regardless of date |
| 4 | Any signs of spoilage: off smell, mold, slimy texture, color change? | Discard | The food should be safe to eat past its quality date, per USDA guidance |
The framework's logic is that each step overrides the printed date. Formula ends the inquiry immediately; "Expires" labels end it next; mishandling ends it regardless of everything else; and only a food that clears all four checks earns an "eat" decision — even if its "Best By" date passed weeks ago.
Empowering Your Food Safety Decisions
Consumers should prioritize proper food handling, storage, and visual and olfactory inspection over printed date labels — except for infant formula, where the federally required "Use-By" date is a strict deadline. The measurable indicators of getting this right are reduced food waste in your household, fewer instances of foodborne illness from misread labels, and growing confidence in assessing whether food is edible. This article teaches principles rather than an exhaustive shelf-life list, and it reflects U.S. federal rules; state and local laws may vary. Start with your refrigerator tonight: check temperatures, check handling habits, and let your senses — not the stamp — make the call.
Sources
- Food Product Dating — FSIS
- 10 Foods You Should Throw Out After They Expire — Midwest Food Bank
- Expiration Dates (Video) — Stop Food Waste
- Foodshare
- HEART
