When our babies are little, it’s our natural instinct to want to do everything we can to protect them! So, where does that leave us with protecting them from germs and bacteria which might have made it onto their feeding equipment?!

Whether you breastfeed, formula feed, exclusively pump or combination feed, chances are you have questioned yourself over sterilising – what needs to be sterilised, how often and until when?!

Why do we need to Sterilise?

Before we get into the detail of the ‘what, how and when’ of sterilising, it’s important to point out here that babies under 1 don’t have the same immune systems as us adults or even older children.

Milk residues can be a breeding ground for potentially harmful bacteria[1] so sterilising your baby’s bottles and feeding equipment will help protect your baby from infections, particularly those which cause vomiting and diarrhoea.

But don’t be daunted by the need to sterilise equipment! It really is straightforward once you get the hang of it and hopefully, this blog will help you to answer some of your questions covering EVERYTHING you need to know about sterilising…

What needs to be sterilised?

Regardless of whether you are breastfeeding or formula feeding, there is typically always something that needs sterilising!

If you’re formula feeding…

Before every feed, you will need to make sure that all parts of your baby’s bottle have been sterilised; including the bottle, teat, lid and any internal parts of the bottle such as anti-colic venting tubes.

If you’re breastfeeding…

If expressing breast milk, the NHS advise that you should sterilise any bottles or containers used to store expressed breast milk before use.

When it comes to sterilising breast pump equipment, this isn’t an area where there is a lot of research, so often advice regarding sterilising breast pumps can differ between professionals.

It’s important to remember though that sterilising will always help to add an extra layer of protection for your baby, which may be particularly important if your baby is less than 3 months old, was born prematurely or has a weakened immune system.

In the UK, the NHS recommends that all equipment that comes into contact with your baby’s milk (including equipment used to collect, store or feed expressed breast milk) is sterilised before every use[2].

However, the Association of Breastfeeding Mothers, along with the Academy of Breastfeeding Medicine, advise that after sterilising before first use, subsequently washing breast pump parts with hot soapy water is sufficient for healthy babies[3].

For comparison, the CDC (Centers for Disease Control and Prevention) in the US recommend sanitising breast pump parts at least once a day[4].

How often you choose to sterilise your breast pump equipment will ultimately be your own personal decision taking into account the health of your baby, what you feel comfortable with and are able to sustain on a daily basis. If you haven’t used your pumping equipment in a while though, it’s always best to sterilise before using.

Remember if you are using breast milk storage bags, these should come pre-sterilised so are ready to use straight away.

Anything else?

As well as baby’s feeding equipment (such as bottles), it is also a good idea to sterilise other items which regularly go into baby’s mouth, like dummies, for the first six months of baby’s life – especially as these items seem to always end up on the floor!

Is it necessary to sterilise weaning equipment?

Once you’ve finally mastered sterilising baby bottles, it is then time for weaning!  Along with a whole raft of questions you may have about weaning, one of them is likely to be along the lines of…. “Do I need to sterilise weaning equipment?!”

Rest assured… if you’re weaning around the recommended age of 6 months, then there is no need to sterilise the equipment you use for food such as bowls, spoons or cups. Washing in hot soapy water or using a dishwasher will be sufficient for these weaning essentials.

However, if you decide to wean before 6 months, it is recommended by the NHS that you do sterilise baby’s feeding equipment until they reach 6 months.

How to Sterilise:

Before you start…

There are a few different methods to choose from when it comes to sterilising, but regardless of what method you choose, there are a few things you need to do first!

First things first; you need to physically clean all parts of the baby’s bottles or feeding equipment first using either hot soapy water or using the dishwasher. If using the dishwasher, make sure all of the hard-to-reach places; particularly inside teats, are thoroughly clean before sterilising!

Once you’re happy all parts are clean, rinse using cold running water to remove any remaining soap suds and you’re ready to go…

TOP TIP: Remember to sterilise all the parts of the bottle separately! For example, don’t assemble bottles until after sterilisation has taken place.

Using the dishwasher to clean baby bottles and breast pumps does not replace the need to sterilise these items!


There are lots of devices on the market to help you when it comes to sterilising your baby’s feeding equipment, either at home or on the go. Essentially, there are 3 main methods for sterilising1:

  1. Using steam
  2. Using boiling water
  3. Using a cold-water sterilising solution

Providing each method is done correctly, all are deemed to be effective, so the method you choose is likely to come down to personal preference as well as how often you need to sterilise items, the price of sterilising equipment and the room you have in your kitchen!

After Sterilising

Always wash your hands before handling any sterilised equipment!

If you can, leave your bottles and teats in the unopened steriliser until you need them. However, once you have opened the lid to the steriliser, even if it is just to remove one bottle, always assemble all the remaining bottles inside the steriliser, being careful not to touch the teats and always ensuring any surface used to assemble the bottles is clean. 

And remember…. Condensation in the bottles is completely normal! This is nothing to be worried about as the water inside the bottles is sterile… just don’t be tempted to dry the bottles as you may inadvertently transfer bacteria from the cloth into your freshly sterilised bottles!

How long do items stay sterile for?

Bottles and teats stay sterile for approximately 24 hours if they have been assembled or left in an unopened steriliser.

When storing expressed breast milk, if you have used a sterile container to store your breastmilk in the fridge or freezer, there is no need to change the container or re-sterilise once milk is inside the bottle.

When is it okay to stop Sterilising?

It’s important to sterilise your baby’s feeding equipment such as bottles and teats until they are at least 12 months old. 2

Once your baby starts crawling and decides to start putting EVERYTHING in their mouth… you might be tempted to stop sterilising any bottles used for their milk (formula or breastmilk) earlier than recommended – But it’s important you don’t!

As I mentioned earlier, milk residues are breeding grounds for potentially harmful bacteria so during the first year of their life it is important to do what you can to help protect their health as much as possible.

By the time your baby has reached 12 months old though, their immune systems will generally be much more resilient.

Although you may be counting down the days until you can stop sterilising, remember that there is no harm if you continue to sterilise bottles for as long as your baby is using them as sterilising will always add that extra layer of protection for your little one….

TOP TIP: Once you do decide to stop sterilising; make sure you always wear rubber gloves when washing up any feeding equipment so you can get the water nice and hot!

Hopefully this blog has answered all of your sterilising related questions… and more!

[1] National Childbirth Trust (NCT), 2019. How to sterilise baby bottles, breast pumps and other feeding equipment. Accessed 7th February 2021 []

[2] NHS, 2019. ‘Sterilising Baby Bottles’

[3] Association of Breastfeeding Mothers, 2019. ‘Expressing Breastmilk’

[4] Centers for Disease Control and Prevention, 2020. ‘How to Keep your Breast Pump Kit Clean’