How Long Is Breastmilk 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. You should be aware of how long is breastmilk good after warming though.

What You Should Know About 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 the 5 methods 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.

Do you know how long is warmed breastmilk good for?

How long does breast milk last after warming? After frozen or refrigerated breastmilk has been warmed it should be used within 2 hours. It will last up to 2 hours at room temperature and should never be returned to the fridge or frozen.

Breastmilk Use Guidelines

It has become a norm for mothers to store pumped breastmilk in the fridge for later use. - How Long Does Breast Milk Last After Warming | Baby Journey
It has become a norm for mothers to store pumped breastmilk in the fridge for later use. Source: health.clevelandclinic.org

Pumping a bottle for your little one is a great option. It allows you to get away for errands or some time to yourself while someone else gives your baby a bottle. To safely store pumped milk until you need to use it, you will need to refrigerate or freeze it, usually in milk storage bags. Then, when it is time for a bottle you will need to warm it.

This begs the question, how long is breastmilk good after warming? Yes, there are strict guidelines for breastmilk use and storage to ensure that it is safe to feed to your baby. If you are wondering just how long is warmed breast milk good for, read on!

Breastmilk storage bags are great for your refrigerator or freezer! - How Long Does Breast Milk Last After Warming | Baby Journey
Breastmilk storage bags are great for your refrigerator or freezer! Source: target.com

how long is breastmilk good after warming?

The CDC advises that once breastmilk that has been stored in the refrigerator or freezer is warmed, it should be used within two hours.

This means that you can warm it with a bottle warmer and feed it to your baby little by little over a period of two hours. Or, you can warm it and feed it to your baby at the end of the two-hour time span. Regardless of when during the two hours you feed it to your little one, there is only a window of 2 hours in which the milk is considered safe for use.

So, how long does heated breast milk last? 2 hours! But what if your baby doesn’t finish it? Can you reheat breast milk after it has been heated?

Can You Reheat Breast Milk More Than Once?

No! At least, not if you fed or attempted to feed your little one. While some people may want to reheat breastmilk again if their little one didn’t finish the bottle, it is not advisable.

I know, dumping all of that liquid gold can be such a bummer! But it is for your child’s safety. Once the milk comes into contact with your baby’s saliva germs enter the milk and it can be a breeding ground for bacteria.

Breastmilk is full of nutrients and can serve as a breeding ground for bacteria when left out in warm conditions for too long. - How Long Does Breast Milk Last After Warming | Baby Journey
Breastmilk is full of nutrients and can serve as a breeding ground for bacteria when left out in warm conditions for too long. Source: vodenglish.news

This is because breastmilk can be considered a “living food”. As soon as it is expressed it contains bacteria from the exterior of your body, the pump parts, and even the environment. However, these bacteria are usually at low levels and won’t harm your little one.

But like other foods that can spoil when left out, they begin to multiply in warm conditions. Once warmed and removed from the fridge or freezer, heated breastmilk is a prime breeding spot.

And though experts may have disagreeing opinions on how quickly breast milk spoils, it is better to be safe than sorry and abide by the 2-hour limit. As a pumping mom I know tossing out unfinished milk (including formula milk!) can be extremely upsetting considering how much hard work it takes to collect it and store it!

You know the rules about how long can heated breast milk stay out, which is 2 hours, but your child didn’t want to eat during that time. Does this mean you can then reheat the milk? Unfortunately, no, it still isn’t advisable because bacteria can grow during the 2-hour span after it was warmed.

If you don’t think your little one will eat in the 2-hour window it is probably best not to warm the milk and leave it in the fridge until your child is hungry.

After all, freshly expressed milk can last in the refrigerator for up to four days. And, after thawing (not heating!) it can stay in the refrigerator for up to 24 hours. Best to wait until your little one is really ready for their bottle!

Can you put breast milk back in the fridge after warming?

We know the answer to how long is breast milk good for after heated is 2 hours. And we know that it isn’t safe to reheat the milk a second time. But more questions arise. Can you put the bottle of breast milk back in the fridge after warming?

You should not keep heated breastmilk back to the refrigerator or the freezer for subsequent use.  - How Long Does Breast Milk Last After Warming | Baby Journey
You should not keep heated breastmilk back to the refrigerator or the freezer for subsequent use. Source: breastmilkcounts.com

Sorry, but it is another “no”. Breastmilk that has been heated should not be returned to the refrigerator or the freezer. As mentioned above, after warmed or even when left at room temperature, the bacteria in the milk begin to multiply. Though there are no concrete studies, experts suspect that the bacteria can reach unsafe levels after two hours.

Some parents may disagree, stating that if you warmed the milk and did not feed it to your baby you can then return it to the fridge for up to four hours. However, most experts follow the rule of “two hours then toss” after warming regardless of if your baby ate some of it or not.

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.)

Benefits for doing this? You’ll be able to make absolutely sure that baby is 100% safe from bacterial growth. And that should be your utmost priority.

Two Ways to avoid leftover milk

There are two ways you can plan ahead and avoid dumping your precious breast milk down the sink at all. They are:-

  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.

How Long Is Heated Breast Milk Good For, a Recap

A good, safe handling of milk whether breastmilk or formula milk will ensure a healthy, well-fed baby.  - How Long Does Breast Milk Last After Warming | Baby Journey
A good, safe handling of milk whether breastmilk or formula milk will ensure a healthy, well-fed baby. Source: webmd.com

Here’s a quick summary on breastmilk handling as discussed thus far:

  • Breastmilk that has been warmed is only good for 2 hours
  • If the warmed milk is not used within 2 hours it should be discarded
  • It is not advisable to reheat breastmilk a second time
  • You should not return warmed breastmilk to the refrigerator or freezer

These guidelines apply to all babies at any age. However, they are especially true for preterm infants or those that may have a compromised immune system.

Two Hours Tops!

Fresh breastmilk is best, but sometimes you have to refrigerate or freeze it. You should then try to warm the breast milk as close to when your baby will be hungry as possible. You only have a two-hour window to feed your little one. Timing it correctly will save you from crying over leftover milk that has to be thrown out because it cannot be reheated or re-cooled.

Do you have a question about how long is breastmilk good for after warming or comment? Let us know below!

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