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Breast milk storage and bottle hygiene

Just like normal milk, breast milk must be stored carefully to stop it going sour. Follow these tips to make sure none of your milk goes to waste.

Getting ready to express

  • Wash your hands
  • Make sure whatever you're collecting your milk in is very clean and dry (you don't need to sterilise it though - this is new advice in Scotland)
  • Use a different container with a lid to store your milk. Again, check it's clean and dry
  • You can get breast milk bags in the baby aisle in supermarkets or pharmacists but these are not reusable


  • Label storage containers with the time and date to make sure you don't use any spoiled milk
  • Store your milk in the fridge or freezer as soon as possible
  • Store at the back of the fridge and not in the door, away from meat products, eggs and uncooked food

Storage times and temperatures

  • You can store your breast milk for up to 3 days in a fridge running below 10ºC
  • Breast milk stored in a fridge running under 4ºC can be stored between 4 and 8 days
  • Freeze your milk if you won't be using it in time
  • Keep an eye on the temperature of your fridge - opening the door frequently can make it rise. If there's no built in thermometer, borrow or buy a fridge thermometer available from kitchenware stores
  • Use a cool bag or box with frozen ice packs to transport milk

Using stored breast milk

  • Defrost frozen milk in the fridge, but if you need it quickly it is safe to defrost under cool, then warm (not hot) running water
  • Dry the outside of the container with a clean towel or kitchen roll before use
  • Use stored breast milk straight from the fridge
  • To avoid overheating never use a microwave, always heat in warm water
  • Use defrosted breast milk immediately - throw away anything unused
  • If it smells sour, it has spoiled. Don't use it!
  • When stored the cream and milk may separate out. This doesn't mean it's spoiled - just gently mix it before use
  • Use a very clean bottle, cup or syringe to feed your baby. There's no need to sterilise. Just clean everything thoroughly in hot, soapy water and completely air dry, checking there's no dried in milk or soap left behind

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Last updated: 16 May, 2019