How Long Does Breast Milk Last?
Freshly expressed breast milk lasts up to 4 hours at room temperature, up to 4 days in the fridge and about 6 months in the freezer. Thawed milk keeps 1 day in the fridge and must never be refrozen.
Breast Milk — fresh
shelf life- Thawed: 1 day in the fridge
- Opened, leftover from a feeding: 2 hours in the fridge
Fridge at 40°F (4°C) or below · freezer at 0°F (−18°C). Freezer times are for best quality; frozen food stays safe longer.
Expressed breast milk is a living fluid with antibodies and enzymes that slow bacterial growth for a while, which is why freshly pumped milk tolerates a few hours at room temperature. That protection fades with time and is reduced by freezing, so thawed milk has much tighter limits than fresh. These times follow CDC guidance for healthy, full-term babies.
How to store breast milk
- Store milk in breast milk storage bags or clean food-grade containers with tight lids, labeled with the date it was expressed; do not use disposable bottle liners or ordinary plastic bags.
- Freeze in small portions of 2–4 ounces to avoid waste, and leave about an inch of space at the top because milk expands as it freezes.
- Place milk at the back of the fridge or freezer rather than in the door, and freeze right away any fresh milk you do not expect to use within 4 days.
- Thaw the oldest milk first, overnight in the fridge or under lukewarm running water; never microwave it, which destroys nutrients and creates scalding hot spots.
- When away from home, milk can travel in an insulated cooler with frozen ice packs for up to 24 hours.
How to tell if breast milk has gone bad
- A distinctly sour or rancid smell or taste, like spoiled cow's milk, that is present soon after thawing or in refrigerated milk.
- Milk that stays clumpy or stringy after gentle swirling; simple separation into a cream layer on top is normal and mixes back in.
- Milk stored beyond the recommended times, even if it looks and smells fine, because harmful bacteria cannot be detected by smell.
- A soapy or metallic smell on its own is usually caused by the enzyme lipase, not spoilage, and the milk is safe, though some babies refuse it.
Bacteria that cause food poisoning usually do not change the look, smell or taste of food. Go by the time limits first, and the signs above second.
Breast Milk shelf life chart
| State | Fridge | Freezer | Pantry |
|---|---|---|---|
| Fresh | 4 days | 6 months | 4 hours |
| Room temperature means 77°F (25°C) or cooler. Frozen milk is best within 6 months; up to 12 months is acceptable. | |||
| Thawed | 1 day | Not safe | 1–2 hours |
| The 24 hours start when the milk is fully thawed, not when it left the freezer. Never refreeze. | |||
| Opened, leftover from a feeding | 2 hours | Not safe | 2 hours |
| Use within 2 hours after the baby finishes feeding, then discard. | |||
Not safe = perishable: no more than 2 hours at room temperature (1 hour above 90°F / 32°C). Not recommended = possible, but quality suffers or it serves no purpose.
Frequently asked questions
How long can breast milk sit out at room temperature?
Freshly expressed breast milk can sit out for up to 4 hours at 77°F (25°C) or cooler, according to CDC. Thawed milk is limited to 1–2 hours. In a warm room, or if the milk was not expressed under very clean conditions, refrigerate it as soon as you can.
Can I reuse breast milk my baby did not finish?
Only for a short time. CDC advises using leftover milk within 2 hours after your baby has finished feeding, and discarding it after that. Bacteria from the baby's mouth enter the bottle during the feed. Offering smaller amounts at a time helps avoid pouring milk away.
Can thawed breast milk be refrozen?
No. Breast milk should never be refrozen once it has thawed. Use it within 24 hours of it being completely thawed in the fridge, or within 1–2 hours once it has been brought to room temperature or warmed.
Why does my frozen breast milk smell soapy?
A soapy, metallic or fishy smell in stored milk is usually due to lipase, a natural enzyme that breaks down milk fat over time. The milk is safe and most babies drink it. If your baby refuses it, talk to a lactation consultant about scalding freshly expressed milk before freezing.
Can I add freshly pumped milk to milk that is already cold or frozen?
Yes, but cool it first. Chill freshly expressed milk in the fridge before combining it with already refrigerated milk, and do not pour warm milk onto frozen milk, since it partly thaws the frozen layer. Date the container by the oldest milk in it.
Related foods
| Food | Fridge | Freezer | Pantry |
|---|---|---|---|
| Infant Formula Prepared |
24 hours | Not recommended | 2 hours |
| Baby Cereal Opened |
Not recommended | Not recommended | 1 month |
| Homemade Baby Food Homemade |
1–2 days | 1–2 months | Not safe |
| Baby Food (Jars) Opened, fruit or vegetable |
2–3 days | 1–2 months | Not safe |
| Milk Opened |
1 week | 3 months | Not safe |
| Baby Food Pouches Opened |
1 day | 1–2 months | Not safe |
Reviewed 2026-09-20. Times follow published USDA FoodKeeper / FSIS, FDA and CDC storage guidance; where sources differ we use the shorter time. How we compile this data.