How to prepare baby formula

Here we provide tips and information on how to make up a baby's bottle using formula milk including how to mix baby formula.

Safe preparation of formula (as recommended by the Department of Health) is really important and has been shown to reduce the risk of infection (see our step-by-step guide below on how to prepare a baby's formula bottle). This is because powdered formula is not sterile and can sometimes contain the bacteria, cronobacter sakazakii and, more rarely, salmonella. The infections caused by them can be very serious and even life threatening. 

You can use ready-to-feed infant formula instead, which can be easier because there is no need to make up a formula feed. This is a more expensive option though and you will still need to make sure bottles and teats are sterilised whatever type of milk you use. In the UK, it’s recommended that you continue to sterilise bottles and teats for as long as you use them for milk.

1. It's important to clean and sterilise bottles and teats, and then leave them to drip-dry.

Washing a bottle

2. Boil enough tap water and leave to cool to no less than 70°C. This is important in order to kill germs that may be present in the powder.

3. Clean your working surface and wash your hands with soap and water.

4. Pour the correct amount of boiled water into the sterilised bottle. 

5. Using the scoop provided, add the correct amount of powder and level off. 

Baby formula baby powder








6. Mix by gently shaking the bottle side-to-side to prevent scalds with hot milk. 

Making a bottle of formula milk safely

7. Cool to the right temperature by holding the bottle under cold running water. Shake a few drops of milk from the teat onto the inside of your wrist, it should feel lukewarm. 

Making a bottle of formula safely

If you want to prepare bottles in advance for the day or night, the World Health Organisation (WHO) says: 'It is safest to prepare a fresh feed each time one is needed, and to consume immediately. This is because prepared feeds provide ideal conditions for bacteria to grow - especially when kept at room temperature. If you need to prepare feeds in advance for use later, they should be prepared in individual bottles, cooled quickly and placed in the refrigerator (no higher than 5°C). Throw away any refrigerated feed that has not been used within 24 hours.'

It's also worth saying that very young babies and babies with poorer immune systems, such as premature babies, are most vulnerable to bacteria. Making up each feed when needed is most important for these babies.

Last updated December 2015

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.

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