How to Tell If Milk Is Bad
Milk that smells sour, looks lumpy or yellowish, or feels thick and slimy is bad. Opened milk usually lasts about 5 to 7 days in the fridge, though it can turn sooner, so the sniff test is your best friend.
Signs Milk has gone bad
- Sour smell. Fresh milk is nearly odorless with a slightly sweet scent. Spoilage bacteria produce lactic acid, which causes a sharp, sour smell.
- Lumps or curdling. Chunks or clumps in the milk mean the proteins have clumped as the acid rose. Don't try to strain and use it.
- Yellowish tint. Milk that turns from bright white to a dingy yellow or off-white has been growing bacteria.
- Thick or slimy texture. If it pours slowly or leaves a slick film in the glass, it's gone bad.
- Sour taste (only after a smell warning). Your nose should flag spoiled milk first. If you take a sip by accident and it tastes sour, spit it out and toss the carton.
Looks weird, but it's fine
- Slight creaminess at the top. Non-homogenized milk separates, with cream rising to the top. Shake it and it's fine.
- Small ice crystals after freezing. Frozen and thawed milk can look grainy or separate. Shake before use; it's best for cooking and baking.
- Slightly sweet or cooked taste. Ultra-pasteurized milk has a mildly cooked flavor from the high-heat process. It's normal.
How long does Milk last?
| Where | How long | Note |
|---|---|---|
| Fridge (unopened) | Up to 1 week past the sell-by date | If kept at 40°F or below |
| Fridge (opened) | 5 to 7 days | Use the date and smell as guides |
| Freezer | Up to 3 months | Leave room in the carton for expansion |
| Counter | Max 2 hours | Discard if left out longer |
How to store it
- Store milk on a middle or back shelf, never in the door, so it stays cold and stable.
- Close the cap or carton tightly right after pouring, and never return poured milk to the container.
- Keep the fridge at or below 40°F, since every 10 degrees of warmth can cut shelf life noticeably.
Use it up before it turns
Frequently asked questions
Does milk go bad before the date?
It can. If the carton sat warm in the car or a warm fridge, it can spoil early. The date assumes steady cold storage, so always smell before you pour.
Is it safe to drink slightly sour milk?
Don't. Sour milk means bacteria have grown, and while a bit of it might not make you sick, it's not worth the risk. When in doubt, throw it out.
Can you cook with milk that's gone sour?
Spoiled milk should be discarded, not used in recipes. Cooking won't reliably make it safe. If you want a tangy ingredient, buy buttermilk or make a fresh substitute with milk and lemon juice.
More food freshness guides
General guidance based on USDA FoodKeeper. Storage times are estimates and conditions vary. When in doubt, throw it out.