Posted on

Storing breastmilk 101

how to store breast milk

Storing breastmilk 101

Yap, you are ready, you read about the benefits of breastfeeding your child, you are ready to latch, and you have prepared to pump 2-3 hourly. But how do you exactly know how to store your breastmilk? How long can you keep your breastmilk at room temperature? How long in the fridge? How long in the freezer etc. These are some of the questions that most mummies have and here I have compile some of the tips on storing breastmilk that I hope this might help you.

How do I store my breast milk?

How you store your breastmilk depends on how soon you want to use it. If you plan to use it within a few days, refrigerating is better than freezing. Freezing destroys some of the substances in your milk that fight infection. However, frozen breastmilk is still a healthier choice for your baby than formula, though.

The rule of thumb to follow while storing milk is

  • Always wash your hands before expressing and handling breastmilk for storage. Keeping everything as clean as possible will make it less likely that bacteria will grow in your stored milk.
  • Keep your breast pump clean. Wash the parts in hot, soapy water, and rinse them thoroughly before sterilising.
  • Use sterilised containers. Opt for plastic bottles or plastic breastmilk bags. Glass bottles may crack or chip.
  • If you’re pumping at work, you can store your milk in a travel cooler with ice packs or in a common space refrigerator.
  • If you need to combine freshly expressed milk with frozen milk, cool the expressed milk first. Don’t add more than there is of the frozen, since you want to avoid the frozen milk thawing.
  • Label and date your bottles and bags, and use up the oldest ones first. If you combine milk from several pumping sessions, label it with the date of the oldest milk.

If you plan to feed baby in the next 24hours, place the milk bag/bottle at the highest deck of the fridge. If you plan to feed baby 24 hours later, you can put the milk bag/bottle in an isolated compartment of your freezer.

It’s helpful to label each container with the date when the milk was pumped (and your baby’s name if the milk is going to childcare providers).

Can I top up fresh cooled milk to frozen/chilled milk?

Frozen Milk

You can add fresh cooled milk to milk that is already frozen, but add no more than is already in the container. For example, if you have 40ml of frozen milk, then you can add up to 40ml of cooled milk.

Chilled Milk

You can add freshly expressed milk to breastmilk that’s already in the fridge, provided it has been expressed on the same day. Bear in mind, though, that you can only keep it until the original milk is five days old.

How do I freeze my milk?

Freeze your milk as soon as you finished expressing your milk. Leave a gap on top of your bag or bottle as your milk expands during freezing.

When freezing, store milk in smaller portions such as 1-3 ounces in order to avoid waste.

How do Thaw my milk?

Defrost frozen milk in the chiller section of the fridge ideally 12 hours before usage.

Once you defrost your breast milk, do not re-freeze it.
Don’t be tempted to defrost or warm your breastmilk in a microwave.

If you need the milk in a hurry, defrost it under cool, then warm, running water, or place it in a bowl of warm water.

Dry the outside of the container before you open it, and use it straight away. Once your baby has started to drink from the bottle, you should use it within 1 hour.

What to look out for

  • Thaw your frozen milk in the chiller section of the refrigerator 12 hours or overnight if you plan to use your frozen milk.
  • Do not shake your bottle if the creamier portion has separated, instead gently swirl your bottle  as shaking will cause some proteins in the milk to break apart.
  • Always use the oldest milk from your supply first. Don’t worry if the oldest is weeks or months old. It is true that the composition of your milk changes over time to suit your growing baby’s needs. However, even older milk, as long as it has been properly stored and handled, is beneficial to your little one.

Some Little tricks

  • Store bags, tightly sealed, flat and stacked. This will speed up thawing time.
  • To have some more extra use from our pump accessories,  give them a quick rinse then throwing them in a large ziplock bag, and storing them in the refrigerator until the next pumping session.
  • Does your milk smell soapy? Most breast milk has a mild or slightly sweet scent, but mothers occasionally report that thawed milk smells soapy. This may be due to enzymes in the milk digesting some of the fat and is probably fine if your baby accepts the milk. If not, scalding (but not boiling) the milk and quickly cooling prior to freezing may solve this problem if baby is rejecting the milk, although this may lower the nutritive content and is not ideal.
  • you can still offer your milk to your baby if you and your baby are experiencing thrush while being treated. After the infection has cleared, however, discard the milk as neither cooling nor freezing kills the yeast.
  • Have some expired milk? Instead of tossing the milk, consider using it for diaper rash, baby eczema, cradle cap, or a good milk bath for your little one.



  1. Smith, Linda J. (1998) “Don’t Shake the Milk“. Bright Future Lactation Resource Center Ltd.
  2. The Academy of Breastfeeding Medicine Protocol Committee (2010). “ABM Clinical Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants (Original Protocol March 2004; Revision #1 March 2010)
  3. Kelly Mom, “My expressed breastmilk doesn’t smell fresh. What can I do?“. July 28, 2011.
  4. Le Leche League International. “What are the LLLI guidelines for storing my pumped milk?“.