Baby with bottle

Sterilising your Baby’s Bottle

Clean and sterile bottles, and all feeding equipment, are essential for safe feeding. Without sterilisation there is a risk that bacteria, viruses and parasites may contaminate the milk, grow and ultimately result in your child becoming ill; from mild gastrointestinal symptoms, thrush or something more serious.

If you decide to bottle feed your baby you must get hold of all the bottle feeding equipment you will need and the means by which to sterilise it before you start the bottle feeding process. This is the same whether you are using formula milk or expressed breast milk.

Sterilising is not the same as cleaning. This is why you need to sterilise bottles even if they have been through the dishwasher at high temperature.

Step one – clean your bottles and feeding equipment

Wash bottles either in the dishwasher (making sure that bottles, teats and lids are facing down so they do not pool with water) or wash with a bottle brush using clean, warm and soapy water. If you have them, you should wash all of the following pieces of equipment:

  • Bottles
  • Teats
  • Lids
  • Retaining rings
  • Caps
  • Any equipment you use for storing powder or prepared formula
  • The milk scoop

It’s best to clean everything as soon as possible after a feed. Take special care when washing teats (turn them inside-out) as milk curds can be difficult to dislodge and any bacteria present in them may even be able to survive the sterilising process. Always be sure to thoroughly rinse off any detergent (soap bubbles) from the equipment before sterilising.

Step two — sterilise your baby’s bottles and feeding equipment

Once all your bottles and equipment are clean, they will need sterilising.

It can be tempting to think that just because everything looks clear and clean, it cannot possibly harbour any bacteria. However, the truth is that bacteria, viruses and even parasites exist at a microscopic level not visible to the human eye and without sterilising your feeding equipment you risk exposing your baby to potentially harmful pathogens.

Your baby’s immune system is still developing and cannot fight off harmful pathogens in the same way you can, as an adult, so sterilisation of feeding equipment is vital to protect you baby. It is a cruel truth of nature that milk and milk powder are in many ways the ideal breeding ground for bacteria so you must always take precautions.

The different types of steriliser

There are four popular methods for sterilising baby bottles and feeding equipment:

  • Steam sterilising: Purpose-made electric steam sterilisers can sterilise multiple bottles and teats at one time and only take ten minutes to complete the process. However, they can be pricey and are not easily portable.
  • Microwave steam sterilisers: These containers are designed for baby bottles and some can also be used as a cold water steriliser when a microwave is not available. You simply load the feeding equipment into the steriliser, carefully following the instructions, put it inside your microwave and heat. Microwave steam sterilisers are easy to use but can become very hot very quickly, so caution is advised.
  • Boiling: Fully immerse your bottles and teats in a saucepan and boil for ten minutes to ensure they are sterilised. This method is quick and effective and does not rely on you purchasing any specialist equipment. However, boiling teats can degrade them quickly, making them stiff, hard and breakable. Depending on the hardness of your water, the bottles may also accumulate limescale.
  • Cold water sterilising: You simply soak all your bottles, teats and other equipment in a specialist non-toxic solution, such as Milton, for at least 30 minutes. Ensure the bottles and teats have no trapped air bubbles and make sure that you have an internal cover or a plunger to keep everything fully immersed. Be sure to change the solution every 24 hours. Cold water sterilising is a great option for those who require a flexible sterilising option that can be used on the move.

Next steps

In order to have confidence that everything remains sterile, you should leave your feeding equipment in the steriliser or pan until you use it. Many mums get into a routine of making up enough formula for a 24 hour-period with freshly sterilised bottles to avoid contamination.

If you must take something out, be sure to handle it with freshly washed and dried hands and to fit teats and lids onto the bottles straight away. When using the bottles, prepare them on a clean and sterile surface.

At what age can I stop sterilising my baby’s bottles and other feeding equipment?

According to NHS advice, all feeding equipment should be sterilised for at least the first 12 months of your child’s life. This is because once a child is one, they are likely to have a more developed immune system.


Successful sterilisation of feeding equipment is essential to the bottle feeding journey. However, the choices you make about sterilising equipment will depend on your individual circumstances.