In some scenarios, it’s not always clear whether breast milk is safe to give to your baby or needs to be discarded. Here are the most common “can I feed my baby this breast milk” questions, and answers according to the available guidelines and information.
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My baby didn’t finish a bottle. Can I reuse it and offer the bottle later?
If my baby drank some breast milk but didn’t finish the bottle, can I feed the leftover milk later?
Yes. You can offer it again within two hours.
Per the CDC, the guideline that we should follow is:
If your baby did not finish the bottle, the leftover breast milk can still be used within two hours after the baby is finished feeding. After 2 hours, leftover breast milk should be discarded.
What’s the reasoning behind this guideline? When your baby begins drinking from a bottle, there will be some bacterial contamination that occurs in the breast milk.
How quickly this will make the breast milk unsafe to consume depends on the room temperature, how long the milk has been stored, and the bacteria present.
As a general guideline (without knowing the individual circumstances of each bottle) the CDC states that offering again within two hours should be safe for consumption. After that, it may not be, and so should be discarded.
If I warmed a bottle and baby didn’t drink from it, can I put it back in the fridge? How long does breast milk last after warming?
If I warmed a bottle of breast milk and my baby didn’t drink any (she went back to sleep), can I put it back in the refrigerator and offer it again?
Yes. You can offer it again within the next two hours.
Per the CDC:
Once breast milk is brought to room temperature or warmed after storing in the refrigerator or freezer, it should be used within 2 hours.
The reasoning here is that bacteria starts to grow more quickly when the milk is warmed.
Can you reheat a bottle of breast milk?
If I’m reusing a bottle within the two hours, should I put it back in the fridge and rewarm it, or just leave it at room temperature?
Either rewarming or leaving it at room temperature is fine – whichever works best for you. Per Kellymom:
If you do save the milk for later use, some mothers re-refrigerate the milk and others leave it at room temperature – no studies have been done, so we don’t know whether one method is preferred. We do know that for any food, refrigeration slows bacteria growth. Milk storage guidelines do not include any warnings against rewarming milk, and many moms rewarm with no issues.
Just be sure to use or discard within two hours of the first warming.
Can I refreeze frozen breast milk?
My milk thawed in a power outage. I’m heartbroken! Can I refreeze it?
This is the worst feeling – I’ve had all my milk thaw due to one of my older kids unplugging my deep freezer.
But unfortunately, you cannot refreeze thawed breast milk, and you need to use it within 24 hours of when it has finished thawing (not from when the power outage started or you took it out of the freezer).
One important thing to note when considering this is that “finished thawing” means that all of the ice crystals are gone. If your breast milk still has ice crystals, it is considered safe to put back in the freezer.
Can I take breast milk out of the fridge and let it come to room temperature?
Can I take my breast milk out of the refrigerator and let it gradually warm up, instead of using a bottle warmer?
Yes, you can. However, there is a time limit on how long you can leave it out.
Again, per the CDC:
Once breast milk is brought to room temperature or warmed after storing in the refrigerator or freezer, it should be used within 2 hours.
So you have two hours once your milk comes to room temperature to feed it to your baby. How long does it take breast milk to come to room temperature when sitting out? I love experiments, so I tested it out.
It took about two hours when I tested it out (room temperature in my Chicago-in-January house was 66 degrees).
How long it will take your breast milk to warm to room temperature will depend on how much milk is in the bottle, what the ambient temperature is, and the composition of the milk. However, I think two hours is a good general guideline.
Can I leave refrigerated breast milk out, and feed it to baby in the middle of the night?
In the past, you’ve recommended letting freshly pumped milk sit out until baby’s first nighttime feeding (within 4-8 hours*). Can I do this with previously refrigerated milk, or does it have to be freshly pumped?
You can, as long as the feeding occurs with four hours – two for it to come to room temperature, and the two that it can sit out according to the CDC guideline discussed above.
So, if your baby goes to bed at 8pm, you take the milk out and go to bed at 11pm, and your baby normally wakes up for a feeding before 3am, that will work fine.
*Note: The guidelines on how long freshly pumped breast milk can be safely left out at room temperature vary. The CDC says 4 hours is the maximum; Kellymom says 4-8, with 3-4 being ideal.
Can I take thawed breast milk out of the fridge and let it come to room temperature?
I’ve weaned from the pump and am feeding my baby from my freezer stash. I want to take some breast milk with me on an outing with my baby. I know I can’t thaw the milk at room temperature. But can I thaw it, and then let previously frozen milk come to room temperature in a my diaper bag before feeding it?
I could not find a clear answer to this question.
There are two parts to the question – a) can I let a bottle of previously frozen milk come to room temperature over time, and b) can I let a bottle of previously frozen breast milk sit out at room temperature until baby is ready to drink it?
We have to answer to the second part of the question from the Department of Health and Human Services:
Once breastmilk is thawed to room temperature or warmed after being in the refrigerator or freezer, use it within 2 hours.
So yes, a bottle of previously frozen breast milk can sit at room temperature for 2 hours.
However, they do not specify how the breast milk must get to room temperature. We know that we can’t thaw milk at room temperature (it needs to be done in the refrigerator or in water), but after it’s thawed, can it sit at room temperature to warm, or does it need to be warmed to room temperature by putting it in a bowl of lukewarm water? I read through a lot of documentation, and was not able to find an answer.
So, if you want to be on the safe side, I would recommend keeping the previously frozen milk cold in a cooler (more options here) and then warming it using one of the methods described here for warming breast milk outside the house.
What “can I feed my baby this breast milk” questions do you have that I missed? Share them in the comments, and I’ll try to find the answer!
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References- Bonyata, Kelly. “Breastmilk Storage & Handling.” https://kellymom.com/bf/pumpingmoms/milkstorage/milkstorage/
- Bonyata, Kelly. “My power went out and I have breastmilk in the freezer – Help!” https://kellymom.com/hot-topics/frozen-milk-power-outage/
- Bonyata, Kelly. “Reusing Expressing Breast Milk.” https://kellymom.com/bf/pumpingmoms/milkstorage/reusing-expressedmilk/
- CDC. “Proper Storage and Preparation of Breast Milk.” https://www.cdc.gov/breastfeeding/recommendations/handling_breastmilk.htm
- Department of Health and Human Services. “Pumping and storing breastmilk.” https://www.womenshealth.gov/breastfeeding/pumping-and-storing-breastmilk
- Englash, Anne, and Simon, Liliana. “ABM Clinical Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants, Revised 2017. https://abm.memberclicks.net/assets/DOCUMENTS/PROTOCOLS/8-human-milk-storage-protocol-english.pdf
Hi
When expressing breast milk into bottles can you store the breast milk in the fridge in the bottle with the teat and teat cap on the bottle?
Or should it be only stored in a bottle with a screw top lid?
As long as the cap is on the teat it’s fine!
I have a 6 week old newborn that loves falling asleep in the middle of feeding sessions. Anyway if I keep a bottle of freshly expressed nreastmilk out for say 4 hours and she ain waking to have it can I put it in the fridge AFTER it’s been sitting at room temperature for 4 hours? 77 degrees f is our room temperature
The CDC would say you could do put it in the fridge until 3 hours and 59 minutes and then after 4 hours exactly it’s bad. 🙂
Picked my son up from daycare and his caregiver said she had just put his bottle in the warmer less than 2 minutes ago. It was still cool to the touch. It was half thawed frozen milk, half fresh from refrigerator. I immediately put it in to a cooler with ice packs and transferred it to the refrigerator when I got home 30 minutes later. Want to still give tomorrow morning before the 24 hr window expires. Will this be ok?
If it was still cool to the touch that’s fine. If it had warmed to room temp or warmer I would have said use within 2 hours. But you should be good!
Thank you Amanda. I did go ahead and give it. Ended up being just after the 24 hr expiration for thawed frozen milk. Not entirely sure as there may have still been ice crystal in it longer than I am thinking. He drank 4 of the 5 oz. Seems to be ok.
Hi. I use a pitcher method and accidentally left a refrigerated pitcher full out at 1030 pm until 420am. I instantly put it back in the fridge. Would you say this is safe to feed if it was closed and doesn’t have bad smell or taste?
Hi Lauren! According to the rules, no – I’m so sorry!
Hi! I moved a days worth of breast milk from the freezer to the refrigerator, and 24 hours later it still hasn’t completely defrosted. Can I still use this if I defrost it in warm water?
Hi Christi – yes! the 24 hour clock doesn’t start until it’s completely defrosted. 🙂
I just want to say THANK YOU for the above scenarios!! I’ve literally looked for four months for this!
For some reason i thought breast milk was safe in the fridge for 8 days. UGH. Do i need to trash everything i’ve frozen?
Hi Gwen, some sources say up to 8 days – it’s confusing. Personally, I wouldn’t trash what you’ve frozen, I would just do four days going forward. But ask your pediatrician if you have concerns. I hope that helps!
Hi, I hope you’re still reading this! Should I dump my breast milk if both my baby and I had a cold while it was expressed? Thank you!
Hi Elisa! No, you can feed it.
I didn’t know you couldn’t freeze breast milk that baby didn’t finish. I would put in fridge right after and freeze the remaining at the end of the day. Unfortunately I don’t know which of my stash was reused breast milk or not. What should I do?
Hi Christina! Oh, that stinks. Honestly, I would ask your pediatrician. They might recommend different things based on your baby’s age, health, whether they were a preemie or not, that kind of thing. Sorry this happened!
Hi question: I didn’t realize it was bad to combine freshly pumped milk into already chilled milk and have some frozen, should I dump it or is it safe to still feed baby? Each bag frozen is from the same day I just didn’t cook down the milk before combining it with previous milk. Thanks in advance:)
Hi Hannah, if you only warmed it once (dumped warm milk into chilled milk one time) I personally wouldn’t dump it. If you did it multiple times, I might use it for a milk bath. Hope that helps!
The AAP has changed this guideline! Look under “milk storage” https://www.aap.org/en/patient-care/breastfeeding/frequently-asked-questions/
Hi! Thank you for the amazing resource! I offered my daughter freshly pumped breast milk but she only drank a few sips from it. Can I heat that milk before offering it to her again in that two hour periof or would reheating it increase the chances of bacteria spreading?
Hi! You can reheat within the 2 hour window according to kellymom.com. Hope that helps!
Hi! I’m a working new mom and breastfeeding. At work, i pump and store my milk in a cooler with ice packs until i get home and then i freeze the milk. Is this ok? I also follow the fridge method with my pumping parts, as i can’t wash all my parts at work. Is this okay as well? Thank you!
Hi Isabelle, that’s fine as far as milk storage goes. Here’s a great video about the fridge hack that might be helpful: https://www.instagram.com/tv/CKUoAsIAu8e/
Hi, my many dint finish the freshly pumped breast milk which was offered to him within one hour after pumping . Can I refrigerate the remaining milk ?
Hi Shiva! It should be used within 2 hours, I’m sorry!
Hi there,
I put my breastmilk from the freezer into the fridge the night before I need it. I thought my baby would wake up for a feeding so I warmed it up ahead of time. I ended up giving her the bottle about 1 hour after I warmed it up but she didn’t finish it. Is the milk still good for 2 hours from the time she started feeding or from the time I warmed it up?
Thanks so much!
Hi Sonji! The CDC isn’t good with nuance but I would say 2 hours from warming. I agree it’s confusing!! Congrats on your sweet baby!
Hi! I pumped 3 bottles at work today and they were refrigerated. I pumped one more bottle after I left work. I forgot to put my ice packs back in the cooler when I left work. Unfortunately I was not going straight home and the bottles were in the cooler in the car without ice packs for ~2.5 hrs. When I got home the previously refrigerated ones were not as cold. Do I need to dump them or can they still be consumed?
Hi Candice! If they were only at room temp for 2.5 hours, they can still be consumed. If you’re nervous, though, you can use them for a milk bath.
I accidentally left fresh pumped milk out for 8 hrs over night in my 75 degree house. I forgot to put it in the fridge before I went to bed. Should I dump it?
I would, I’m sorry! Or use it for a milk bath if it’s not spoiled. Sorry Hanna!
Hi! Thanks for this resource.
1. can I keep freshly expressed pumped milk out for 4 hours and THEN store it in fridge after 4 hours if Cam doesn’t drink it ? Or should I throw it away after 4 hours? I know I can keep the milk out upto 4 hours..
2. If I take pumped milk from fridge and warm it, how long can it stay out ?
Hi Aarthi! up too 4 hours is okay but AFTER 4 hour you’d want to dump. 🙂
You should use within 2 hours of warming!
I have a bottle warmer with a “constant warm” function. If I put breast milk in the warmer and it stays at 95 degrees F, how long can I keep it warm before I have to discard it?
Hi Lauren! 2 hours. 🙂
I took a bottle out to feed baby while we were out but she didn’t need it. The bottle is untouched. Can I refrigerate or does it need to be thrown?
If it got to room temp, you should use within two hours. Otherwise you can refrigerate. Hope that helps!
This is great info for us grandmothers-who-babysit, too. Thank you so much!
You’re welcome Carol! 🙂
Hi! Thanks for all the info that you provide. I’m having trouble figuring out a day out with frozen bagged milk. Would I be able to thaw it overnight in the fridge and for a day trip and then pack the partially thawed milk in a cooler bag with ice packs (like a lunch cooler) and let it keep thawing like that? Or would I have to just take it almost completely frozen and keep it in the cooler? I would rather not buy a portable warmer as we don’t really go out (but I will if that’s the safest route). My LO doesn’t mind cold milk so it doesn’t need to be warm, just completely thawed.
Hi Patty! I would fully thaw it overnight (finish in cold water if it’s not fully thawed) and then pack it with ice packs and keep it cold to feed. HOpe that makes sense!
Thank you ladies for the amazing helpful tips! This page is def provided me a lot of comfort bc I am a new mom and breastfeeding and I wasn’t sure of a lot of things brought up or mentioned here today!
Thank you for your super informative website! I’ve been wondering, if baby doesn’t finish their bottle, can I freeze the remaining milk?
Thank you!
Amber
Hi Amber, no, sorry! You can reoffer it for 2 hours and then you should discard it. You could freeze it to use in a milk bath though?
Hi! I just got back from a 7-hour road trip on Sunday night. Before leaving, I added a couple of bags of breast milk to an insulated cooler with a block of ice. Once I made it, the block of ice had melted down into pieces (there was still ice present) so the milk was completely submerged in ice water. I immediately put it in the refrigerator. So I am wondering if the milk is still good. And if so, for how long.
Hi Amber, if there were still ice crystals, which is sounds like there were, you should use it within 24 hours of it finishing thawing in the fridge. Hope that helps!
Great Read, had the answer to every single question I have ever asked on breastfeeding. Thanks Mirabel
Hi Amanda, i have few questions and I hope you’re still reading this 😅
1. Can i add freshly expressed milk with previously refrigerated milk to feed my baby? Incase i didnt pump enough and need to add few more ml. If yes then should I warm both together or just the cold milk before mix both together
2. Once previously frozen milk has been thawed using warmer, but false alarm because my baby go back to sleep, can I put back the warmed milk in the fridge and use it within 24hrs or 4hrs or 2hrs? Then warm it back before the next feeding time.
Really hope you can answer these. Thank you so muchh!!
Hi Farhah! For #1, if you’re feeding immediately, that should be fine. I’d warm the cold and then add the freshly expressed.
For #2, you can use it within 2 hours after warming.
Hope that helps!
Hi! I warmed previously refrigerated milk and added an ounce of formula to it (8 oz milk, 1 oz formula). My baby fell back to sleep and it’s now been out for two hours – can I still use it?
Hi Jane, so sorry, but after 2 two hours I wouldn’t feed it. I would use it for a milk bath though!
Hello! So if my baby drinks fresh breast milk that has already been out for 4 hours but doesn’t finish do I still have 2 more hours? Or is it leave out for 2 hours and they can finish in another 2 hours?
I think as long as your house is on the cooler side (less than 72 degrees) that’s okay. If not, I would maybe put it in the fridge and re-warm. (The CDC doesn’t go into this much detail, so this is a guess/what I would do, not anything official.)
I have a frozen stash built up and want to know if I need to dump it all? Soo I just found out that you need to chill freshly pumped milk before adding it to refrigerated milk. Well I have a pretty big frozen stash that I did not follow that rule with and I’ve actually defrosted and fed my baby to bags worth. Should I throw out all that milk and is my baby at risk since she did drink about 2 6ounce bags? Also do I need to let freshly pumped milk get chilled in fridge before putting it directly into the freezer?
Hi Jennifer, I think if your baby hasn’t gotten sick she’s probably fine. I would ask your pediatrician but I think my approach if it were me would be different if you dumped warm milk in once versus all day long (so the milk is warmed and warmed and warmed). I would dump the latter I think.
You don’t need to chill it before putting it in the freezer.
Thank you for such a thorough and helpful page!
Thank you so much!
How many degrees is ‘room temperature’? Thank you Amanda!
Hi! The CDC defines it as 77 degrees and under 🙂
Does freshly expressed milk need to cool down to room temperature (mine can be really warm right after pumping) before storing in the fridge/freezer?
No it doesn’t! 🙂
My baby didn’t finish her bottle. I want to give it to her again within two hours but I’m sure it’s not enough to fill her belly so she goes back to sleep. Can I add freshly expressed or refrigerated milk to the leftovers, warm it all together and then give to my baby the next time she wakes. She’s just under 3 weeks right now and I exclusively pump.
Hi Julia! No, the concern is that the bacteria from the unfinished bottle would then have time to grow. Even if you dilute the milk, the bacteria will still be there. You need to discard it. Sorry!
Is it possible to place refrigerated breast milk in a thermos to keep it cold, if we were to leave the house for a few hours? The thermos would only be used for baby’s breast milk and I would wash it in the dishwasher before use.
Thank you!
Yes, I think this would be fine! An insulated bag with an ice pack might be easier (so you can keep it in the bottle) but I see no issue with using a Thermos as you describe.
I’ve been asking the question about caffeine output.
I’ve been told by lactation nurses that caffeine is most potent after 2-3 hours of consumption. My question is what if I drink more caffeine than recommended but don’t pump for 5,6 or 7 hours, does that milk still have the high caffeine content or has it lost some of that over the hours?
I think it is probably like alcohol, where it leaves the milk as it leaves your blood. However, I’m not 100% sure, sorry!
My husband was trying to get a head start on heating a bottle of breast milk because he thought the baby was waking up from her nap, but she fell back to sleep. So he asked me what he should do with the bottle. Given the above information, even though she didn’t drink from it, I told him use within 2 hrs to be safe. Is that right? Or because she didn’t drink from it yet, would it still be good for a longer period?
You got it right!
Oh my gosh! These are literally all the questions I have had over the last 8 months of my baby’s life. Thank you, thank you!
Hi! I gave my baby thawed milk, he didn’t finish it – can I offer it to him again in a couple of hours? Should I put it back in the fridge or toss it? Thanks
I would offer it again within two hours and then toss. Personally I would just keep it at room temp.
Do you know how long breast milk can stay in the fridge before you freeze it? Can it be in the fridge for days and then frozen or does it need to be frozen immediately?
It can be in the fridge for a few days (up to 4, per the CDC) and then frozen. If you know you’re going to freeze it, it’s better to do that right away – but if not, it’s okay.