If you’re pumping breast milk for your baby, you may be wondering, how long can breast milk sit out? And how do I store it?
First of all, good for you! Breastfeeding isn’t always easy, but you’re making sure baby is getting the very best food even while you’re away. In this post, we’ll unpack how long breast milk can sit out, plus answer some breast milk storage questions.
Tips for pumping and storing breast milk
If you are pumping breast milk for baby, there are a few guidelines that will make life much easier and ensure that your milk is safe.
- Wash hands before pumping.
- Use containers that were properly sanitized with warm water and soap.
- Store milk in 1–2 oz amounts (or whatever you know your child will finish at a feeding).
- Leave an inch or so of space at the top for expansion if putting in the freezer.
- Date each container.
- Freeze or refrigerate as soon as possible. If a refrigerator isn’t available, an insulated cooler is the next best choice.
Can leftover breast milk be served?
The potential problem with serving leftover milk is that bacteria from baby’s mouth may enter the bottle and contaminate the milk, so it’s best to avoid feeding leftovers if possible.
However, many moms have trouble with this answer, since breast milk is like liquid gold, and wasting even a small amount is devastating to a pumping mom. Many sources say that despite the possibility of bacteria growth, it is safe to feed leftover breast milk.
One study found that some breast milk that was refrigerated for 8 days had less bacteria than when it was expressed. This is because breast milk contains live cells and antibodies that help fight bad bacteria.
According to Ruth Lawrence, MD, author of Breastfeeding, A Guide for the Medical Professional:
“Breast milk can safely stand at room temperature for 6 to 8 hours and need not be discarded if the first feeding attempt is incomplete. In contrast, formula must be refrigerated and discarded after the first feeding attempt because it contains no antibodies or infection protection factors.”
So, a good rule of thumb is to avoid feeding leftovers by storing breast milk in smaller amounts. If you do feed leftover breast milk, offer it within a few hours of the last feed, ideally (possibly up to 6–8 hours later).
How long can breast milk sit out?
It’s always best to refrigerate or freeze milk right away, but what if you’re at work? Or what if you forgot about a bottle on the counter? Luckily, breast milk is a live food that can withstand being left out for a relatively long amount of time.
Freshly expressed milk can be stored at room temperature for 6–8 hours. If the room is particularly warm, it’s more like 4 hours.
Freshly expressed milk can be stored in an insulated cooler with an ice pack for 24 hours.
Fresh milk can be stored in the back of the refrigerator for 3–8 days (assuming it was collected as carefully as possible). Ideally, it should be used or frozen within 3 days. Thawed milk can stay in the refrigerator for 24 hours. Don’t refreeze.
Fresh breast milk should be stored in the back, away from the door, and should be used within 6 months.
Fresh milk can be stored in a deep freezer for 6–12 months.
Thawing and heating frozen milk
The best way to thaw frozen breast milk is gradually in the refrigerator. If that’s not an option, then place the bottle of frozen milk in lukewarm water (or hold it under the tap). Increase the temperature of the water slowly until the milk is no longer cold (but not hot). Here’s more information on how to warm breast milk.
Never microwave human breast milk. The microwave may cause hot spots in the milk that can be very dangerous for baby’s sensitive mouth. Microwaving may also destroy some of the antibodies in the milk. Who wants that?!
Keep in mind that once milk is refrigerated or frozen, it loses some of its antioxidants and bacteria-fighting abilities. It’s still the very best food for baby but will not last as long as fresh milk.
Final thoughts on breast milk storage
Human milk is pretty amazing. It can sit out for much longer than any other food and still be safe. It can be frozen and still be nutritious. What kind of a wonder food is this?! Oh, right—nature’s perfect food for baby, which comes from your amazing bod, mama!
So, next time you leave some breast milk out accidentally, you likely won’t need to throw it away. Considering how much time and energy it takes to pump that precious liquid gold, that’s music to the ears!