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Bottle feeding

New safety advice

Parents need to be aware that powdered infant formula milk is not a sterile product. Even though they are sealed, tins or packets of milk powder can contain bacteria, such as Enterobacter sakazakii or Salmonella.

Infections caused by these bacteria in formula milk are very rare, but when they do happen they can be fatal. Low birth weight and premature babies, and babies under six weeks old are most at risk from these bacteria, but it’s important to try to destroy the bacteria when making up formula milk for any baby. The bacteria can be destroyed by making up the milk with water at a temperature of around 70°C. In practice, this means boiling the kettle and leaving it to cool for no longer than 30 minutes.

If you are likely to need a bottle in a hurry, pour freshly boiled water into a flask, seal it and use this to make a fresh formula milk when necessary. This is safer than storing made-up formula milk in the fridge. Alternatively, you could use ready-to-feed liquid formula.


The cleaning and sterilising instructions are the same, whether you are using expressed breastmilk or infant formula milk.

All the equipment you use for bottlefeeding your baby needs to be washed in hot soapy water, rinsed and sterilised.

You need to keep sterilising your feeding equipment until your baby is at least six months old.

Methods of sterilising include:

Before making up a bottle of formula milk


Be aware that powdered infant formula milk is not a sterile product.


Is your feeding equipment thoroughly clean and sterilised.


Always check the temperature before feeding your baby.

If you are still worried, contact your GP or midwife.