May 27th, 2009 • Comments: 0 • by Wendy • PumpingResources

Why Does My Expressed Breastmilk Smell Bad?


If you're new here, you may want to subscribe to our RSS feed.  Thanks for visiting!


I recently came across this fantastic resource on the Lansinoh website and wanted to share it with you!

"In very rare cases, some mothers who have meticulously expressed and frozen their milk for later use have discovered to their dismay that all their frozen milk has turned rancid.  This happens when a mother produces milk that is high in lipase, the enzyme that breaks down fat in the milk. Depending upon the level of lipase in her milk, some mothers notice this rancid smell after their milk has cooled in the refrigerator; others, notice it only after the milk has been frozen for a while.  Thankfully this doesn’t happen often, and this can be prevented. 
a freezer full of breastmilk
It is suggested that every mother who is planning to freeze her milk should freeze some test batches of milk and thaw it out after a week or so to be sure it has not become rancid.  If the mother finds that after freezing and thawing her milk that it has a rancid smell, she can prevent this from occurring in the future by heating her expressed milk to a scald right after collecting it and then quickly cooling and freezing it.  Scalding inactivates the lipase.  Once the milk has acquired the rancid smell, however, treating the milk will not help.  It is not known whether or not this milk is safe for the baby however, most babies refuse it because of the taste."

You can find more information on this subject on the KellyMom website.  She states that the milk is in fact NOT harmful to your baby, but the stronger the taste, the more likely that he or she will refuse it.

Have you ever found that your breastmilk "turned" after refrigerating or freezing?  If so, did you throw it out or did your baby drink it anyways?  I never encountered this personally, however I would love to hear your stories!  Please drop me a comment below.

{"Feeling More Secure with My Breastmilk Stash!" by Diana Schnuth is licensed under CC BY-NC-SA 2.0}

blog comments powered by Disqus

Lucy Cowems says:

I have encountered this with my baby. She will consistently take a bottle of expressed breast milk at first, but will stop feeding after about an ounce. She becomes very fussy and is obviously still hungry. I always noticed the milk had a sour (but not bad) smell. Today, my husband dropped some of the milk on my wrist and I tasted it--yuk, soapy! My daughter has never gotten badly sick from the milk but may have had some extra gassiness and once had a VERY green stool (also a sign of ++lipase?).

Posted on July 16, 2009

Wendy Armbruster Bell says:

Thanks for the comment Lucy!

Here is a great article from iVillage.com speaking to the green stool/gassiness issue. According to this article, it is actually caused by a foremilk/hindmilk imbalance. Read on...

http://parenting.ivillage.com/newborn/nbreastfeed/0,,40wl,00.html

Perhaps you need to empty your breast by pumping longer to get the hindmilk? I'm not a lactation consultant, but that is my first thought.

Best,
Wendy
www.PumpEase.com

Posted on July 16, 2009

Lauren says:

I've just discovered that my frozen milk is high in lipase. I tasted a drop that got on my finger, and then tasted some more to be sure. It is really terrible. But my son doesn't seem to mind it. I will scald in the future before freezing but in the meantime I have 200 ounces of frozen milk that will all have this sour taste. I have a 5-day trip coming up and I don't have time to collect enough milk all over again so he will just have to deal with this milk while I'm gone. But then I think I'll throw out whatever is left and start fresh with the scalding process.

Posted on October 13, 2009

Wendy Armbruster Bell says:

Thanks for the comment Lauren. It's a good thing that KellyMom.com says that your milk is OK for your son to consume and doubly good that he isn't refusing it considering you are heading out of town. I love happy endings! Have a good trip.

Posted on October 13, 2009

Lorraine says:

I'm so happy I came across this article. Finally I know what is wrong with my breastmilk! My son is now 8 months old. I've tried many times to freeze my breastmilk always being very careful everything is sanitary etc When I used the milk he would eat a little then start screaming and refuse it... he would still be hungry and eat from breast or fresh expressed bottle but never what had been frozen. It is always hard to get him to calm down afterwards, he seems a little gassy and very fussy. This caused me to start tasting my breastmilk (yuck, i know!) before i fed it to him... but i was so worried i was giving him bad milk. Most of the time my fresh expressed milk is okay, sometimes though it tastes "soapy" and then makes me gag, when this happens now i don't feed him it. Interestingly enough my son had colic for the first 3 months of his life, related i don't know?? I do have a Q though?.. would scalding my breastmilk before freezing it nil the nutrient value in it?

Posted on January 1, 2010

Wendy says:

Hi Lorraine,

Thanks for your comment. To answer your question I went back to the Kelly Mom site here: http://www.kellymom.com/bf/pumping/lipase-expressedmilk.html

She says, "Scalding the milk will destroy some of the anti-infective properties of the milk and may lower some nutrient levels, but this is not likely to be an issue unless all of the milk that baby is receiving has been heat-treated."

So no, it does not "nil" the nutrient levels, just reduce them. As I'm sure you're already aware, even with lowered nutrient levels, your breastmilk is still far better for your son than formula.

I hope this helps!

Wendy

Posted on January 1, 2010

Colleen says:

After tasting some refrigerated breast milk just now I thought for sure it was off..I even made my husband taste it as well which made him gag! My Son has no issues with it, just glad to know that there is nothing wrong with it. Thanks so much for the info.

Posted on January 7, 2010

Wendy Armbruster Bell says:

@Colleen - always glad to help!

Posted on January 7, 2010

Renee says:

I have just started pumping just to have a bottle for Dad in case he needs it before I get back from running errands. The first time I fed it to him at room temp and it went well. The second day I pumped was this past Monday. I put it immediately in the fridge. We went to use it Thursday night. The baby screamed the whole time my husband tried to feed him. I took it from him and noticed the sour smell right away. I'm wondering if I just leave it for one day rather than 3 or 4 if the same thing would happen. I haven't tried it yet. If the lipase problem is there, does the smell show up as soon as it chills?

Posted on January 30, 2010

Wendy Armbruster Bell says:

Hi Renee,

If you go to the Kelly Mom site here: http://www.kellymom.com/bf/pumping/lipase-expressedmilk.html you will read that an excess of the enzyme lipase can begin to break down the milk fat soon after the milk is expressed (which leads to the soapy, sour or rancid smell). Therefore, it would make sense that after one day your milk could smell OK and after three it may not. It is due to the process of breaking down which begins almost immediately after expressing. Does this help?

Wendy

Posted on January 31, 2010

Renee says:

Thanks Wendy! Yes. This gives me hope. I'll start experimenting tomorrow.

Posted on January 31, 2010

Wendy Armbruster Bell says:

You're wlelcome Renee - make sure you read the Kelly Mom site - it is a wealth of information! :-)

Posted on January 31, 2010

Trish says:

I have this same problem and didn't realize it until my baby was 7 months old. I never fed him frozen milk, only the sitter. I was unaware of the bad smell. I have a whole freezer full of milk. I did not want to throw it away and found that the milk banks will take it. I am donating all my milk (700+ ounces) to the milk bank. I wish I would have found out about this sooner.

Posted on May 21, 2010

Wendy Armbruster Bell says:

@Trish - Thank you for sharing that milk banks will take milk with a high lipase content. I guess because they pasteurize it, it is fine for consumption?? Did they explain it to you? I'd love to hear more!

Posted on May 21, 2010

Allison says:

Wow, I am so glad I found this! But sooooo sad because I have about 300 ounces in the freezer that my little boy REFUSES to eat and I go back to work on Monday! I want to start scalding my milk from now on, but what if I can'y immediately scald it? ( I will be pumping at work and don't have access to do that until I get home each evening! ) I wish I had figured all this out sooner but I am glad there is an explanation!

Posted on August 12, 2010

Wendy Armbruster Bell says:

Hi Allison,

Thanks for your comment. I'd go to our Facebook page and ask Amy (she moderates our page for us and is a Certified Lactation Educator). My thoughts are that if you refrigerate it at work and scald it as soon as you can after you get home it might still be OK. If you read Renee's comment above - she said it took 3 days for her milk to smell/taste bad. So you'd have to do an experiment.

I hope that helps. Amy is a wealth of information so I'd love to hear what she has to say...

Here is a link to our page...
http://www.facebook.com/PumpEase

Posted on August 12, 2010

Erika Stanley says:

I think we are experiencing this issue as well. My question is can I just put the bottle (milk and all) in a pan of hot water? I would hate to have to transfer from bottle to pan to freezer bags. How would you know if you get it to the right temp?

Posted on September 13, 2010

Wendy Armbruster Bell says:

Hi Erika,

Good question! As far as the temperature, you could use a thermometer (heat to 180F), however KellyMom.com simply says to heat until you see tiny bubbles around the edge of the pan.

I spoke to Amy, our resident CLC and this is what she said:

"First off, if her baby doesn't mind the milk, there's no reason to treat it at all. (There's actually no evidence that lipase is truly the culprit; that's just the best educated guess of the lactation community.)

If the baby won't take it, though, I guess it depends on what kind of collection bottles she's using. If they're glass, I guess maybe it's ok? I wouldn't do it with plastic. It's also good to combine the milk before freezing; the baby gets a more consistent composition, then (though it's certainly not necessary).

So, I'd recommend just putting it in the pan collectively. An IBCLC would be better equipped to answer this, though."

Sorry we couldn't be more help!

All the best,

Wendy

Posted on September 18, 2010

Kelly says:

Thank you for all the information!! My first son never seemed to have any problems with my frozen breastmilk!! My second son would not take a bottle at all! As soon as I smelled it, I could not blame him! It's just sad that I have so much of it already frozen and it will now have to be put in the trash!

Posted on November 6, 2010

Wendy Armbruster Bell says:

Thank you for your comment Kelly. It is a shame that your son won't take your already frozen breastmillk, however it is good that you found out now as opposed to later and can start rebuilding your stash! All the best.

Posted on November 6, 2010

Katie Cordsen says:

Sooo glad I came upon this post. Every time I tell my other lactating friends about how gross my milk tastes and smells they don't get it!!! I've thrown out a few thinking they were rancid, but due to a minimal supply (I only make 24 ounces in 24 hours) I can't toss even a drop! My son has never minded the taste and he's a very healthy little 3 and a half month old. Soooo maybe the excess lipase isn't a bad thing? I hope so! I don't think I will have time to scald milk and if my baby is fine with the taste and isn't fussy or gassy then I'm thinking it's ok?

Posted on November 28, 2010

Wendy Armbruster Bell says:

Thanks for the comment Katie and welcome to our blog. Like I mentioned in my post KellyMom.com (a GREAT resource) states that the milk is not harmful to your son. If he doesn't refuse it, keep on keepin' on! :-)

Posted on November 28, 2010

penelope says:

My baby took thawed milk with no issues. She then started to reject bottles last week after a few ml. This is when I noticed that the milk had a sour smell. This was only for a batch of frozen bags I had though. She is taking the bottles again now, and I noticed the sour smell isn't there anymore. It might had something to do with my stock at the time. But the experience has opened my eyes that the sourness happens, and I'd have to watch out for it.

Posted on January 10, 2011

Wendy Armbruster Bell says:

Thanks for your comment Penelope. I'm glad this article has made your more aware of this issue.

All the best,

Wendy

Posted on January 10, 2011

Yulia says:

I have quite a lot of frozen milk that smells pretty bad too, and my baby would not drink it... I wonder if you could scald it now, after defrosting? Would that help the smell? :(

Posted on January 18, 2011

Lynn says:

My son is 3.5 months old. He started refusing the bottle at around 2.5 months after we got home from vacation. I wanted to introduce the sippy cup to him so I decided to thaw some of my frozen milk. I hadn't had the chance to try it yet & I have read about the soapy taste that happens when breast milk is frozen. OMG does it ever smell and taste bad!! My husband was so disgusted because he wanted to taste it as well. It was a 2.5 month old bag so I thought maybe it went bad so I opened a few more and smelled them while still frozen and they all had the same smell. 2 weeks ago I switched to a different brand and I decided to thaw one of those and they tasted and smelled normal!!! Could it be the type of plastic they are stored in???

Anyway, for the last week I've been storing them immediately in the deep freeze without storing in the fridge first to make sure they are frozen quicker. The ideal freezer temperature is 0 degrees F (-17 degrees C) and make sure there's minimal air in the bag and that it is completely air tight. Any bit of air will ruin the milk. (As with most frozen food.)

I'm hoping that this new batch of frozen milk with these bags (Nuk) don't end up going bad. I'd like to wean my son but have a big enough supply to get him through the first year.

Posted on February 4, 2011

Wendy Armbruster Bell says:

@Yulia - no scalding it after the fact will not help the smell/taste.

@Lynn - you would have to check the new bags after the same amount of time as the old ones. Some milk turns right away, some takes a while.

The only way to inactivate the lipase (which is the cause of the unpleasant taste/smell) is by scalding it.

See KellyMom.com for more information or drop us a line here again.

Posted on February 5, 2011

Lori says:

I had this problem with my first son, and I unfortunately didn't know to scald the milk until he was 9 months old, and I had a deep freezer full of expressed milk that I threw away because I had been told there was no fix. My plan had been to stop expressing milk when my son was 9 months and use what I had frozen. I was so broken hearted, I wish that this had been mentioned in my breastfeeding course, just as an FYI for something to look out for and what to do to "fix" the lipase issue. It would have saved a LOT of frustration and heartache!!!Knowing what to do now, I am checking my expressed milk with my second son, and running my own testing... I have spread the word to every mom I know who is breastfeeding/ expressing their breastmilk. Thanks for putting this out there!!!

Posted on February 14, 2011

Wendy Armbruster Bell says:

Thanks for your comment Lori!

Posted on February 14, 2011

Amy says:

My milk supply has been great and my daughter is now three months old, but the past couple of days she has been refusing my breast milk so I smelled it and its sour even the milk I freshly express is sour smelling and she wont drink it. Is it time to switch to formula?

Posted on March 20, 2011

Wendy Armbruster Bell says:

Hi Amy,

Thanks for your comment. Are you saying that as soon as your milk is expressed she won't take it or has it been in the fridge or at room temperature for a while?

If the latter, you will need to scald your milk immediately after expressing.

Let me know...

Wendy

Posted on March 20, 2011

alyssa says:

Just to ask, if I scald some of those that have not turned bad after defrosting.. is it ok? I am so afraid that the moment they are defrosted, they will start to have the lipase smell quickly within 24 hours.

Posted on May 18, 2011

Wendy Armbruster Bell says:

Hi Alyssa,

Thank you for your comment. Do you know that you have a lipase problem? You could try defrosting some milk and put it into two containers, scald one and not the other and compare I guess, however from my understanding, you would need to scald the milk as soon after expressing as possible as it starts to break down right away ONLY if you have excess lipase though. See Kelly Mom and the comments above for more information. I hope that helps. :-)

All the best,

Wendy

Posted on May 18, 2011

Stephanie says:

So relieved to find this blog! I work full time and pump so my hubby can feed our 5 month old. It has been going well...but I did notice a funky smell in milk that have been in the fridge for 3 days (that's usually the longest it's there). I freaked out and poured it down the drain! *huge sigh*. Now, after the weekend .... Same thing. Milk I pumped Friday smells like a cross between metal and sulfur. This time though... I tasted it. And it tasted fine to me. We will see how it goes today... Thanks for all the info and sharing, Ladies! Good to know I'm not alone.

Posted on August 1, 2011

Wendy Armbruster Bell says:

Thanks for stopping by Stephanie!

Wendy

Posted on August 1, 2011

Sarah says:

Ooooooh! My poor husband! I have been telling him for months now that he needs to rinse the bottles better to get the soap out of them! LOL. Its me, neverming then. My LO's have been drinking EBM for months so they don't mind the taste. And it doesn't make them sick.

Posted on October 2, 2011