You pull the milk out of the fridge, take a sniff, and are not quite sure. Is it fine or is it off? And what does the date on the carton actually mean, because it definitely does not say “expires on”?
The short answer: Yes, milk goes bad, and it follows a more predictable pattern than most people realize. Opened regular pasteurized milk lasts 5 to 7 days in the refrigerator from the day you open it, assuming consistent cold storage at 38 to 40°F. Unopened, it is often good for a few days past the sell-by date. The date on the carton is a quality guide for retailers, not a hard spoilage date. Your nose is a more reliable indicator than any printed date. UHT or shelf-stable milk is a different story and lasts months unopened without refrigeration.
For a complete dairy and food storage reference, see our Food Storage Guide.
Milk: At a Glance
Opened, regular pasteurized: 5 to 7 days in the fridge from the day opened, not from the printed date.
Unopened, regular pasteurized: Often a few days past the sell-by date if kept consistently cold.
UHT / shelf-stable, unopened: Up to 6 months at room temperature (varies by brand).
UHT / shelf-stable, opened: 7 to 10 days refrigerated.
Room temperature limit: 2 hours maximum. 1 hour above 90°F.
First spoilage sign: Sour smell, before any visible curdling.
Slightly sour but not curdled: Usable in baking for most healthy adults. Not for drinking.
Freezing: Up to 3 months. Best for cooking and baking after thawing.
Key Takeaways
Opened regular pasteurized milk lasts 5 to 7 days in the fridge from the day of opening, per FDA guidelines, assuming consistent refrigeration at 38 to 40°F.
The sell-by or best-by date on the carton is for retailers, not a hard expiration for consumers. Trust your senses over the date.
The first sign of spoilage is a sour smell. Curdling, lumps, and a yellowish tinge follow.
Milk stored at the back of the fridge lasts longer than milk stored in the door, which is the warmest and most temperature-variable spot.
Milk left at room temperature for more than 2 hours should be discarded per USDA guidelines, even if it still smells fine.
Milk is also sensitive to light. Leaving it on the counter exposes it to light, which can cause an oxidized off-flavor even before bacterial spoilage is detectable.
Slightly sour milk not yet curdled can be used in baking for most healthy adults. It should not be given to children, pregnant women, elderly individuals, or immunocompromised individuals.
What the Date on Your Milk Carton Actually Means
This is the source of most milk confusion, and it is worth getting right before anything else.
The date printed on a milk carton is almost never an expiration date. It is most commonly a sell-by date, which tells the retailer how long to display the product. Some cartons use “best by” or “use by” language, which reflects peak quality rather than a safety cutoff.
What Federal Regulations Actually Say
The FDA does not require manufacturers to
