How to Safely Store Breastmilk


So… you’ve managed to express some amazing breastmilk for your baby! Breastmilk is incredible and has anti-infective properties within it to help stop the growth of bacteria. However, we still need to be careful to avoid any bacteria entering the precious milk you have expressed and to keep the milk as safe as possible.

If you are harvesting colostrum the midwife may have given you small syringes to hand express into. Ideally, these should have small caps to put on them. Make sure you label the syringe with your name, hospital number (should be written or printed on your maternity records), breastmilk (so it is identifiable what is in the syringe) and the date the milk has been expressed. You can also put the syringes into a sandwich bag and seal it.

When expressing, ensure good hand hygiene and you will need sterilised containers or breast milk storage bags which you can purchase from local high street chemists. Storage bags are single-use and take up minimal space in the fridge or freezer!

Expressed Breastmilk can be at room temperature for 6 hours; if exceeding this time it should be discarded.

If wishing to store expressed breastmilk then aim to refrigerate it as soon as possible after expressing.

Storing smaller amounts of expressed breastmilk can reduce any wastage too (many women will tell you they have cried over spilt breastmilk!)

Fridge Storage

  • Up to 3- 8 days at 4 degrees Celsius or lower.
  • You can purchase a fridge thermometer online to be accurate.
  • If the fridge is running higher than 4 degrees Celsius or you are not sure then use the milk within 3 days.
  • Always store breastmilk in the back of the fridge away from eggs, meat and uncooked foods; never store breastmilk in the door of the fridge.
  • If the fridge temperature rises above 4 degrees Celsius after 3 days (for example a power cut!) use within 6 hours or discard it.

Freezer Storage

  • 2 weeks in the ice compartment of the fridge.
  • 6 months in the freezer if it is below -18 degrees Celsius.

If you cannot use a fridge then you can use a cool box or bag

  • Use ice packs and change them at least every 24 hours.
  • Protect your milk from direct contact with the ice packs so that the milk not freeze by wrapping the ice packs in kitchen towel.
  • You can transport breastmilk in this way as long as the storage and transportation time does not exceed the recommended storage time.
  • Defrosted breastmilk should not be transported as should be used immediately.
  • If transporting breastmilk with no ice packs then use within 4 hours.

Remember the more you open the fridge door (or cool bag) the more likely the temperature will rise so try to check the temperature every time you use the fridge or open the cool bag.  

Defrosting breastmilk

  • Defrost the breastmilk slowly in the fridge until it has completely thawed out; this usually takes 12 hours to fully defrost and then use immediately.
  • If you need to use it sooner you can defrost it in a jug of warm water or running it under warm water, use as soon as it is fully defrosted.

Warming Breastmilk

  • You can feed your baby expressed breastmilk that is straight from the fridge if your baby is happy to drink it cold.
  • If you would like to warm it up to body temperature you can place the bottle into a jug of water or hold it under running warm water.
  • Ensure you check it is not too hot to feed to the baby by putting a few drops onto the inside of your wrist. Ensure the teat does not touch your skin so that the teat of the bottle remains sterile.
  • It is normal for the fattier breastmilk to separate and sit on the top of the expressed milk so you can gently swirl it in the bottle to allow it to mix again. Avoid shaking it.
  • Never use a microwave to warm or defrost expressed breastmilk as this can cause ‘hotspots’ inside the milk which can burn your baby’s mouth.

*Remember these guides are for healthy term babies. If your baby is sick or premature please discuss the storage and transportation of expressed breastmilk with your midwife, neonatal doctor or neonatal nurse to ensure your baby is kept as safe as possible.

If bringing expressed colostrum into the hospital please discuss with your midwife the hospital protocol for transportation, labelling and storage of expressed colostrum as these may vary within different maternity units.


Breastfeeding Network

NHS Expressing & Storing Breastmilk

Kelly Mom Milk Storage