Breast Milk Storage Times

These guidelines are for:

• For healthy, full-term babies. If your baby is premature, immune-compromised, etc, talk to your doctor about how to store breast milk.
• Milk expressed using best cleaning practices 

Storage Times for Freshly Pumped Milk

Room temp (77°F or colder) – up to 4 hours 

• When you’ve finished a pumping session, you can leave the milk sitting out at room temperature if your baby’s next feed will be within 4 hours. 
• For example, most babies eat every 2-3 hours, so for pumping sessions during the day, it’s fine to leave it out. But some babies sleep longer at night, so for nighttime pumping sessions, you might want to refrigerate it as soon as you’re done pumping, so you don’t have to wake up again to put the milk away if your baby is still sleeping.
• If you plan on using older milk from the fridge or freezer for the next feeding, it’s best to refrigerate the fresh milk right away.
• If you accidentally leave a bottle of milk out longer than 4 hours, it may be ok for up to 8 hours if the room isn’t too hot, and if it was expressed under very clean conditions (handled with clean hands, using clean pump parts, etc).

Fridge (40°F or colder) – up to 4 days

• If you don’t plan on using the milk right away, or if it will be longer than 4 hours before your baby’s next feeding, you can store the milk in the fridge for up to 4 days.
• If you know you won’t be using it up within 4 days, it’s best to freeze it as soon as possible.
• If you forget about a bottle of milk in the fridge, it may still be good for up to 8 days if it was expressed under very clean conditions (handled with clean hands, using properly cleaned pump parts, etc) and stored properly (in the back of the fridge, not on the door, away from meat and eggs, etc).

Freezer (0°F or colder) – depends on type

There are 3 different types of freezers, and storage times depend on the type of freezer you’re storing the milk in. 

• Freezer compartment of a refrigerator – 2 weeks
  Older styles or hotel mini fridges have a freezer compartment inside the main fridge. These tend to be opened more frequently and are warmer than other freezers, so it’s best to use the milk within 2 weeks.
• Freezer – 3-6 months
  For the typical, self-contained freezer, breast milk can be stored for 3-6 months for best quality. Milk should be stored towards the back of the freezer, not on the door.
• Deep freezer – 6-12 months
  Deep, chest freezers tend to be colder and are not opened as frequently as the one in your kitchen, so breast milk stored in there will keep longer and should be used within 6-12 months for best quality.

Cooler with Ice Pack – up to 24 hours 

• If you’re on-the-go and pumping away from home, you can store your breast milk for up to 24 hours in an insulated cooler with an ice pack.
• Try to avoid opening and closing the cooler too much, and only open it when you really need to.

Leftover from a Feeding – 1-2 hours 

• Occasionally, your baby might not finish the whole bottle at a feeding. In that case, you can offer it again within 1-2 hours.
• To avoid wasting milk, you can put 2-3oz in the bottle to start, then add another 1 oz at a time if your baby is still hungry. 

Storage Times for Thawed Milk

The following are storage times for breast milk that has been fully thawed. Breast milk should be thawed slowly in the refrigerator for best quality, but it can also be safely thawed in a bottle warmer, in a bowl of warm water, or under warm, running water. Do not thaw breast milk at room temperature, in the microwave, or in boiling water.

Room temp – 1-2 hours

• Once thawed, breast milk can be kept at room temperature and used within 1-2 hours.
• It’s not recommended to put thawed milk back in the fridge after 1-2 hours, once it has been at room temperature.

Refrigerator – up to 24 hours 

• Once thawed, you can keep breast milk in the refrigerator for 24 hours.
• That is, 24 hours from the time it has fully thawed (has no more ice crystals), not from the time you took it out of the freezer.

Freezer – Never refreeze

• It’s not safe to refreeze breast milk once it’s been thawed.
• There haven’t been many studies done on refreezing breast milk specifically, but what we know about food in general is that freezing, thawing, and refreezing really destroys the quality of the food and makes it much more susceptible to the growth of harmful bacteria.

Power outages and accidentally leaving the freezer door open

• Partially thawed milk can be refrozen if it still has ice crystals in it. Temperature fluctuations can affect the quality, so it’s probably best to use up that milk first.
• If the power ever goes out, avoid opening the freezer. Once the power comes back on, check on your milk. If it’s only partially thawed and it still has ice crystals in it, it’s fine to refreeze it.

Cooler – not recommended 

• It’s hard to keep a cooler at a consistent temperature, and there aren’t many studies on storing breast milk in coolers. Until more research is done, it’s not recommended to store thawed milk in a cooler for very long.
• If you do need to keep thawed milk in a cooler for some reason, it’s safe to use it within 2 hours.
• It may be good for longer if your cooler is cold enough and you don’t open the cooler until you’re ready to use the milk, but remember you’re doing this at your own risk.