How long is breast milk good after warming?

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How long is breast milk good after warming

We’ve all been there: You or another provider feeds your baby, and horror of all horrors, there’s leftover milk in the bottle.

Maybe baby fell asleep before finishing the whole bottle. Maybe he’s really full and just can’t possibly drink anymore. So many reasons!

Anyway, your first instinct might be to stick the excess milk back in the fridge. I mean, it is liquid gold, right?

Not so fast.

How long is breast milk good after warming, anyway?

Expressed breast milk

Before we answer the question about what to do when baby doesn’t finish his/her bottle, let’s back up all the way. We all know freshly expressed breast milk is the best way to meet baby’s nutritional requirements. Delivering all of it to baby right away is even better. According to Mayo Clinic , the longer you store breast milk (whether in the fridge or freezer), the more the vitamin C in breast milk will dissipate. Read 5 method on how to make breast milk fattier.

Even more fascinating, breast milk expressed when a baby is a newborn won’t meet your baby’s needs when he or she is even a few months older. Giving it to the baby relatively soon after expressing it is your best bet.

However—we all live in the real world and know that a stockpile of frozen breast milk is such a necessity.

Answer to the all-important question—How long is breast milk good if baby doesn’t finish the bottle?

Okay. You’ve grabbed the frozen breast milk from your deep freeze, swished it around in warm water to thaw it all, you’ve fed baby and his tummy is full (are you exhausted yet?) Then, WHAT to do with that leftover milk? (Best practice vs. what’s convenient, anyway.)

Believe me, I know how tempting it is to stuff the milk back into the fridge—even milk that’s been sitting on the counter after…. well, who knows how long? It’s really, really hard to dump it down the sink. (Been there, done that, and cringed as it went down the drain.)

There are several ways you or another provider can handle the leftover milk:

  1. You can feed it to baby later. Thawed breast milk is best at room temperature up to one to two hours and is still viable to feed to baby up to three or four hours later. This is especially tempting if baby normally drinks the amount you originally offered and you’re fairly certain he will be hungry again later.
  2. You can put thawed breast milk in the refrigerator for up to 24 hours. Again, this is just another option for reuse—and it will give you more flexibility and time to try and feed baby the same milk again.
  3. You can throw it away if you’re not sure that baby will finish it at all. Benefits for doing this? You’ll be able to make absolutely sure that baby is 100% safe from bacterial growth.
  4. Never, ever refreeze thawed breast milk. According to Bfmed, no recommendation can be made at this time about the refreezing of thawed milk.

Why can’t breast milk be refrozen?

Once frozen milk is brought to room temperature, its ability to inhibit bacterial growth is lessened, especially by 24 hours after thawing. Previously frozen milk that has been thawed for 24 hours should not be left out at room temp for more than a few hours.

2 Ways to avoid leftover milk
There are couple of ways you can plan ahead and avoid dumping baby’s breast milk down the sink at all. 1. Instead of expressing lots of milk and then storing it all together in one storage bag, consider breaking it up into smaller quantities, about three or four ounces at a time instead of five or six.

This practice minimizes waste and allows for easier thawing, too. (It’s always best to fill breast milk storage containers only three-fourths full, anyway, to allow for expansion in the freezer.)

Whether you use Lansinoh Breastmilk storage bags or put the expressed milk directly into a bottle, storage is oh-so-important when it comes to the care and keep of the foodstuffs for your precious bundle.

2. Make sure baby is actually hungry before you feed him/her. If baby is just looking for a snack and it’s not actually feeding time, you may be setting yourself up to waste breast milk before you even start the feeding.

Sidebar: Thawing methods for frozen breast milk

The best way to go about thawing frozen breast milk is to stick it in the refrigerator the night before you plan to use it. If you’re in a hurry (like I am most of the time), you can also thaw it by swishing it around in a clean bowl of warm water. Here are a couple of don’ts:

  • Don’t heat a frozen bottle in the microwave.
  • Don’t heat milk quickly on a stove.

Below video shows how to thaw and heat frozen breast milk:

Why not? Obviously, milk from the microwave can be too hot for baby’s tiny mouth, but heat can also affect the milk’s antibodies.

Major takeaways for anyone feeding baby:

  1. Expressed milk should be fed to baby as soon as possible.
  2. Thawed breast milk should be downed by baby within two to four hours.
  3. Thawed breast milk can also be put back in the refrigerator for up to 24 hours.
  4. Never, ever refreeze thawed breast milk.
  5. Always use clean bottles, wash your hands, etc. before feeding your baby. Also, to prevent bacterial growth, make sure your pumping supplies are as clean as possible.

Follow these tips, and you and your baby’s other care providers should know exactly what to do!

Please leave comments or questions on this article below!

The Author


Hi, my name is Schianne, wife to my high school sweetheart and mother of a beautiful and clever little girl. Click here to learn more about us.

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