When Breastmilk Goes Sour: 8 Things That Might Be Causing It

Milk can easily go sour and while it can be discouraging, there are certain mistakes that are easily fixed. Posted by Shalmali on momjunction.com. MomJunction is your friend, philosopher, and guide – all rolled into one. We are a place to stop for a while and hang out with likeminded people, a place to learn and to teach. Image courtesy of Tatyana_Tomsickova via Bigstockphoto.


While women have been breastfeeding for ages now, first-time mothers still find it difficult to cope with the ins and outs of nursing their babies. With the minimal information they have, mistakes are bound to happen. For example, the breast milk can easily become sour. But, don’t get discouraged. Most of these problems are fixable. When it comes to nursing your baby, you may not be an immediate expert. But, with the right information, you can come around, and maybe, able to master the art too.

Breastfeeding being essential for babies, you may have to express your milk at some point or the other. When you begin pumping, it might be difficult to use all that milk at once. And, this is where the problem comes. Once you store the milk, chances are that it may turn sour and you might have to dump it all. So, here we bring you some tips to stay way ahead of the ‘milk’ game:

1. Keep Checking The Temperature

We all know that milk gets spoiled at high temperatures. So, the temperature is what you need to keep in mind when storing breast milk. Whether you keep the milk in the refrigerator or on the countertop, just ensure that the temperature doesn’t go above a particular point.

2. Don’t Store It In Just Any Container

The breast milk shouldn’t be preserved in some random container. It is important to ensure that the container doesn’t leak and is sealed properly. Otherwise, bacteria might cultivate in the milk. You can go for the leak-proof containers or freezer bags specially designed for breast milk.

3. Store The Milk In Back Portion Of The Fridge

Did you know that the refrigerator doesn’t have a constant temperature throughout? No, right? This new piece of information can really help you when it comes to milk storage in the fridge. It is important to ensure that the milk is kept in the coolest place possible in order to avoid spoilage. While you may have to do a lot of work managing the fridge space, keeping it in the back portion (the coldest area) is worth it.

4. Ice Trays Don’t Work

It has been a common trend to freeze the milk in an ice tray. But, thawing can be a really time-consuming process. And, it is best to thaw the milk overnight in the fridge. This won’t work though if you are in a hurry. You can use the breast milk storage tray instead since it is easier to thaw only the amount you need.

5. Clean Hands It Is!

The best way to keep the breast milk fresh is to wash hands before expressing it. Typically, mothers do this because it is pure common sense. However, it can be hard to remember this minute detail when you are rushing right before your little one is about to wake up. But, this one is an essential step. Bacteria and germs don’t really knock the door before coming.

6. Labels Are Important

If you label the breast milk before storing it, you will eliminate the possibility of several potential mistakes. It will help you keep a tab on when a certain breast milk bottle was expressed. And, how long it has been preserved for.

7. Use The Oldest One First

Taking the previous point forward, use the oldest breast milk first. This is the milk that is going to get spoiled before the other ones. So, try to get rid of this one first. Expressing milk is quite a time-consuming process. So, it is not really a good feeling to throw away the effort just because you were a little too late.

8. Stay Away From The Microwave

You can give the milk at room temperature to your baby and there is no need as such to warm it. But, women still decide to warm it up at times. It is not like the infant formula. So, avoid warming the milk on a stove top or in a microwave.

Just follow these tips and you may not have to worry about the breast milk becoming sour anymore. Happy breastfeeding!