It can be hard to know what the best sterilising method for your baby’s feeding equipment is and how to do it. So here we give you the lowdown…

Why do I need to sterilise my baby’s feeding equipment?

A baby’s immune system is not as well developed as an adult’s (Crawley, 2018). So sterilising all your baby’s feeding equipment helps to protect them against illnesses, particularly diarrhoea and vomiting (NHS, 2019a). That’s why, in the UK, the NHS recommends that all equipment used for collecting, storing or feeding expressed breastmilk or formula milk for babies is sterilised before use (NHS, 2019a).

You might not think it but milk provides an ideal breeding ground for the bacteria that could give your baby an infection (Renfrew et al, 2008). Sterilising gets rid of any micro-organisms that could cause harm.

How long do I need to sterilise bottles and other feeding equipment for?

The NHS recommends sterilising all feeding equipment each time you use it for at least the first 12 months of your baby’s life (NHS, 2019a). Unfortunately, washing items in a dishwasher is not considered as an alternative to the sterilising methods described below (NHS, 2019a).

Do I still need to wash feeding equipment before sterilising it?

Yes, it’s still important to wash your baby’s feeding equipment. As soon as possible after you’ve used bottles, teats, breast pumps and any other milk collection, storage or feeding equipment, thoroughly wash them in warm, soapy water.

If you’re using a dishwasher, make sure you place bottles and teats face down, so they don’t fill with dirty water. Using clean bottle and teat brushes will help you reach each part of the bottle, teat or breast pump.

After washing, rinse all equipment in clean, cold, running water before you sterilise it (NHS, 2019a).

Which method of baby bottle sterilisation is best?

We can’t say for sure which method of sterilisation is more effective than another (Renfrew et al, 2008). So you might want to consider what suits you best to help you decide whether to boil items, use a cold water sterilising solution or a steam steriliser.

Your decision might depend on how often you need to sterilise items and how far in advance you tend to plan. Some sterilisation methods take longer than others.

You might also consider the size of your kitchen and what equipment you already have.

Cold water sterilising

Cold water sterilisers use chemical tablets that dissolve in water to create a sterilising solution or they come as a ready-made sterilising solution. Items need to be submerged in cold water for at least 30 minutes before you use them (NHS, 2019a). But once you’ve made up the solution, you can leave items in it for up to 24 hours as long as the lid is closed.

How to cold water sterilise baby-feeding equipment

This can be a good way of sterilising a large number of items so they’re ready for use as soon as you need them. Here’s how you do it:

  • Use a clean, watertight container with a well-fitting lid.
  • Make up the sterilising solution in accordance with the manufacturer’s guidelines.
  • Try to make sure all items remain fully submerged in the solution and that there are no air bubbles. Items should be held in place by a floating cover or plate.
  • Leave the items in the solution for at least the length of time specified by the manufacturer and follow the guidance on how often to change the solution.
  • Remove items from the solution immediately before use. Shake off any excess solution or rinse with cooled boiled water from the kettle (not the tap).

(NHS, 2019b)

Steam sterilising

Many steam sterilisers can be used in a microwave while others plug into the mains. Some microwave steam sterilisers can also be used as cold-water sterilisers.

It’s possible to buy re-usable steriliser bags for use in the microwave. This might be a more convenient option when you’re travelling or if you don’t think you’ll need to sterilise equipment very often.

How to steam sterilise baby feeding equipment

  • Follow the steam steriliser manufacturer’s instructions, as the length of time it takes to sterilise items will vary from one steam steriliser to another.
  • Ensure the openings of bottles and teats are facing downwards in the steriliser.
  • Again, check the manufacturer’s guidelines for information about how long you can leave equipment in the steriliser before it next needs to be sterilised.

(NHS, 2019a)


Boiling items is a good way of sterilising if you don’t have a steam or cold-water steriliser.

Some parents find this method particularly useful in the very early days. If your newborn is not latching or breastfeeding effectively, you can hand express some colostrum and feed it to them using a small cup or teaspoon you’ve sterilised (see Expressing and storing your milk for more information).

How to boil baby feeding equipment to sterilise it

  • Bring a saucepan of water to the boil.
  • Submerge the items to be sterilised in the boiling water for at least 10 minutes.
  • Remove items just before use.

If you do use this method on a regular basis, some items may be damaged by the heat so might need replacing more regularly (NHS, 2019a).

What to do after sterilising

  • You can leave sterilised items in the steriliser or pan until you need them. If you do take sterilised items out, you’ll need to put the teats and lids on the bottles immediately.
  • Clean the area that you’ll be using to prepare the feed or assemble the pump.
  • Wash your hands thoroughly before preparing the feed or assembling the pump.

(NHS, 2019a)

Expressed breastmilk

Breastmilk contains ingredients that limit the growth of unwanted bacteria but you’ll still need to store and handle it carefully to prevent unwanted bacteria contaminating the milk (Hands, 2004). See our articles Expressing milk using a breast pump and Expressed Milk: Your questions answered.

Any breastmilk that’s left an hour after your baby has started drinking from the bottle should be thrown away (NHS, 2019c). And you’ll need to thoroughly wash and sterilise the cup, bottle or spoon and the washable parts of the breast pump just before you use them again (NHS, 2019a).

Formula milk

Powdered infant milks are not sterile so it’s important that they’re made up in line with the instructions on the packet. This will get rid of most of the micro-organisms that may be present (Crawley, 2018). See our articles Step-by-step guide to preparing a formula feed and What if I need to formula feed my baby away from home?

Any formula milk that’s left in the cup or bottle at the end of the feed should be thrown away (NHS, 2019b). And you’ll need to thoroughly wash up and sterilise the cup, bottle or spoon just before you use them again (NHS, 2019a).

Sterilising when out and about

Going out for the day or going on holiday can make the practicalities of sterilising, storing expressed breastmilk or making up formula more challenging. So if you’d like to talk through how to do this when away from home, you can speak to one of our Breastfeeding Counsellors by calling our Infant Feeding support Line (see below).

Where can I go for support?

You can speak to one of our NCT Breastfeeding Counsellors about any aspect of feeding your baby by calling the NCT Infant Feeding Line on 0300 330 070. The lines are open from 8am to midnight every day.

You might also find it useful to talk things through with your midwife or health visitor (NICE, 2015).

This page was last reviewed in November 2019.

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 NCT Infant Feeding Line on 0300 330 0700. 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.

You might find attending one of our Early Days groups helpful as they give you the opportunity to explore different approaches to important parenting issues with a qualified group leader and other new parents in your area.

Make friends with other parents-to-be and new parents in your local area for support and friendship by seeing what NCT activities are happening nearby.

Crawley H. (2018) Infant milks: a simple guide to infant formula, follow-on formula and other infant milks. First Steps Nutrition Trust, London. Available from [Accessed 6th November 2019].

Hands A. (2004) Expressing and storing breastmilk. Breastfeeding Network, Paisley. Available from [Accessed on 8th January 2020].

NICE (National Institute for Health and Care Excellence). (2015) Quality Statement 6: formula feeding. Available from [Accessed on 4th November 2019].

NHS. (2019a) Sterilising bottles. Available from [Accessed 4th November 2019].

NHS. (2019b) Step-by-step guide to making up a formula feed. Available from [Accessed 4th November 2019].

NHS. (2019c) Expressing and storing breastmilk. Available from [Accessed 8th January 2020].

Renfrew M, McLoughlin M, McFadden A. (2008) Cleaning and sterilisation of infant feeding equipment: a systematic review. Public Health Nutrition. 11(11):1188-1199. Available at  [Accessed 6th November 2019].



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