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How to store expressed breast milk

This article provides safety tips for storing expressed breast milk and information on when to use breast milk storage bags.

Expressing and storing breast milk

You will need to sterilise anything you keep milk in and store your breastmilk covered. If you are expressing by hand, you can use a wide mouthed jug or bowl. Most breast pumps screw directly on to a bottle. The milk can then be fed straight to your baby or stored in the fridge or freezer immediately.

In terms of storing breast milk, because it is full of anti-infective properties it keeps well in the fridge. If your fridge stays at less than 4ºC the milk is safe for up to five days. If you’re not sure of the temperature or it is higher, it is best to use it within three days. Otherwise it should be stored in the freezer. Studies differ on how long it retains its protective properties when frozen, but up to two weeks in the freezer compartment of a fridge and up to 6 months in a freezer that stays at -18ºC or lower is recommended as safe.

If you don’t have a fridge, for instance when you are at work, you can store your breastmilk in a cool bag with ice packs, and refrigerate or freeze the milk when you reach home.

If you are expressing small amounts to be given to your baby soon, you can add expressed milk to the breastmilk that is already cooled in the fridge, but its better to have several small containers if you can.

Frozen breastmilk should be thawed slowly in the fridge or at room temperature (never in a microwave) and should not be refrozen. Once it has warmed to room temperature, it should be used or thrown away.

Breast milk storage: Safety tips

  • Keep refrigerated breastmilk at the back of the fridge, as it’s colder.Label and date each quantity of breastmilk and use the ‘oldest’ first from your store.
  • Freeze breastmilk in small quantities in covered ice cube trays, small bottles or breastmilk bags
  • Small amounts of breastmilk defrost more quickly, and you don’t need to defrost more than you need at any one time.If you are expressing milk for a premature or sick baby in hospital you will be given bottles and told how best to store your milk.
  • It is important that any containers that the milk touches (for example pumps, bottles, cups and spoons) are cleaned and sterilised each time you use them.

FAQs about expressing and storing breast milk

Is it all right to give my baby cold expressed breastmilk (EBM), straight from the fridge, or straight after it’s been defrosted?

Nutritionally, it makes no difference and there’s no evidence babies need their milk heated, but some babies may prefer milk at body temperature. The safe way to heat up a bottle of EBM is to stand it in a jug of warm water – though do be careful about scalds, and keep your baby well away from the jug. Before you give it to your baby, shake out a few drops onto your wrist. Warm it just enough to take the chill off. Heating milk in a microwave can lead to uneven heating which can burn a baby’s mouth. It is therefore advisable not to use a microwave to defrost or heat breastmilk.

How much milk am I likely to need for one feed?

This is always going to be a very rough estimate as babies differ so much. Very young babies can only take a tiny volume – maybe only a few mls at a time. Older babies take more. Your baby’s appetite may be greater on some days than on others. However, a very rough rule of thumb is to leave at least 100mls for every feed, plus some extra, until you can predict from your own experience what your baby’s needs are likely to be.

How should I feed my baby expressed milk?

The most common way to give your babyexpressed breastmilk is in a bottle. The alternative is to use a special feeding cup, an egg cup or a plastic syringe for feeding expressed breastmilk. These methods may be best for very new, ill or pre-term babies who have not yet learnt to feed from the breast effectively. They’re also more practical for giving very tiny amounts of breastmilk (or colostrum – the milk you produce in the early days).

Further information

NCT supports all parents, however they feed their baby. If you have questions, concerns or need support, you can speak to a breastfeeding counsellor by calling our helpline on 0300 330 0700, whether you are exclusively breastfeeding or using formula milk. Breastfeeding counsellors have had extensive training, will listen without judging or criticising and will offer relevant information and suggestions. You can also find more useful articles here.

National Breastfeeding Line (government funded): 0300 100 021.

Healthtalkonline.org has a comprehensive library of face-to-face interviews where parents share their experiences about breastfeeding, birth, parenting and many other issues.

NHS Choices has information on bottle feeding and breastfeeding in public.

Best Beginnings has video clips from the 'Bump to Breastfeeding' DVD.