How to sterilize baby bottles - top tips from the experts and moms

How to sterilize bottles - you're not alone in wondering.

How to sterilize a baby bottle illustrated by baby ottles
(Image credit: Getty / Future)

Learning how to sterilize baby bottles, whether you are combi feeding or bottle feeding is vital, and having a good sterilizing routine will make it easier. Also, don't worry, we promise that you aren't alone in wondering how to do this.

There are several options that parents can choose from to ensure clean baby bottles. These range from cold water, steam, boiling, and the more recent addition of UV. As with many aspects of parenting, there are plenty of choices and no right or wrong way to clean your baby's bottles – the most important thing is that they are cleaned properly and thoroughly – even before you start sterilizing. 

Lesley Bland is a registered midwife at MyExpertMidwife. She says, “However you choose to sterilize your equipment, washing it all first in hot soapy water and then rinsing is just as important as sterilization.” Depending on the health and age of your baby, guidance about how long to sterilize bottles is open to interpretation. Here, we’ll debunk the sterilization myths and find out what the experts suggest.

 How to sterilize baby bottles 

Firstly each part of the bottle – from teat to lid and the bottle itself – needs to be separated, and washed thoroughly with hot, soapy water, ensuring any dried, stuck-on milk is washed away. And it’s also key to keep bottle brushes clean and dry between each use. In addition to this, there are multiple ways you can sterilize baby bottles, which we'll go through below. And, while it might sound obvious, clean hands are a must before you even begin to take apart the components of a baby bottle, otherwise, you undo all your hard work sterilizing.

Sterilize with boiling water

  • First, check that the items you want to sterilize are safe to boil.
  • Boil the feeding equipment in a large pan of water for at least 10 minutes, making sure it all stays under the surface.
  • Set a timer
  • Remember that teats tend to get damaged faster with this method.
  • Regularly check the teats and bottles are not torn, cracked or damaged.

Sterilize with cold water

If you choose cold water sterilizing, this method uses chemicals, which are mixed with cold water. Brands such as Milton (View at Boots, £2.99 for 40 tablets) are then activated in the cold water. 

  • Follow the sterilizer fluid/tablet manufacturer’s instructions
  • Leave feeding equipment in the sterilizing solution for at least 30 minutes.
  • Change the sterilizing solution every 24 hours.
  • Make sure there are no air bubbles trapped in bottles or teats.
  • Keep a tight lid on the sterilizer.

If you are using a microwave sterilizer, it’s important to refer to manufacturer guidelines as models differ.

Why do I need to sterilize baby bottles?

“To ensure they are free from harmful bacteria and to reduce the risk of infections or illnesses," Kate McGilly, midwife at the Portland Hospital, part of HCA healthcare tells us. She reminds us how vulnerable young babies are and why keeping their feeding equipment clean is vital. "Newborns and young infants have developing immune systems that are more susceptible to infections. Sterilizing bottles helps eliminate bacteria, viruses, and other pathogens that may be present on the bottle or other feeding equipment. If you are using powdered formula, it is crucial to sterilize the bottles to remove any potential contaminants that may be present in the powdered formula itself.”

Generally, the advice to sterilize is until 12 months old. However, experts suggest you consider your own baby’s general health. Kate goes on to tell us: “For older infants, once babies reach around 3 months of age and show no signs of a compromised immune system or illness, sterilizing bottles may become less necessary. Thorough cleaning with hot, soapy water after each use is usually sufficient. However, it is still important to maintain good hygiene practices and ensure bottles are cleaned properly.”

Which method of sterilizing is best?

“It really comes down to personal preference and budget,” says Lesley from MyExpertMidwife  Parents have plenty of options when it comes to how to get bottles sterile.

Cold water - Kate McGilly explains: “The cold-water sterilization method involves using sterilizing solution or tablets mixed with cold water to soak the bottles and lids. Follow the recommended duration and guidelines provided with the sterilizing tablets or solution.”

Mom of one Sophie found cold water sterilizing to be the simplest method: “I used two different methods to sterilize my baby bottles. I used a microwave steam sterilizer and I also used Milton cold water sterilizing tablets, which I found to be an easier method as I did not have to wait for them to cool. Placing them into the Milton solution also took less time.”

Boiling - A simple method of sterilizing, Kate tells us: “Boiling is a common and effective method. Place bottles and bottle lids in a pot of boiling water for around 10 minutes. It is important to ensure that all parts of the bottles are fully submerged during the boiling process.”

Steaming - You can steam bottles, too. Portland Hospital midwife Kate explains, “Electric steam sterilizers are widely available and offer a convenient and efficient method of sterilization. Follow the manufacturer’s instructions for proper use.”

Lesley from MyExpertMidwife adds, “Microwave sterilizing can be quick, easy, and cheap but check the size of your microwave and the size of the sterilizer before buying.”

UV - The newest mode of sterilizing, UV is also the priciest. Kate from The Portland Hospital tells us, “There are UV sterilizers available that use ultraviolet light to kill bacteria and pathogens. These devices can be effective, but it’s essential to follow the manufacturer’s instructions and ensure that all parts of the bottles are exposed to the UV light.”

But as Lesley Bland from MyExpertMidwife reminds us, how you sterilize comes down to choice. “Ultimately, the choice of sterilization method depends on personal preference, convenience, and the availability of resources. Whichever method you choose, it is crucial to follow the instructions carefully and maintain good hygiene practices when handling and storing bottles to ensure your baby’s safety and well-being.”

What to do after sterilizing

You can leave sterilized items in the sterilizer or pan until you need them but the majority of manufacturers advise either using or re-sterilising after 24 hours. If you do take sterilized items out, you’ll need to put the teats and lids on the bottles immediately. Clean and disinfect the area that you’ll be using to prepare the feed or assemble the pump, or use the upturned lid of the steriliser. Then wash and dry your hands before handling sterilised equipment. Better still, use some sterile tongs.

Drying bottles hygienically is vital, too. The Centers for Disease Control and Prevention (CDC) remind us that the safest and most hygienic way of drying baby bottles is by allowing them to air dry on clean paper towels, not drying with a dish cloth or tea towel or allowing them to rest on a drying rack which could be harboring germs.

Sterilizing when out and about

Obviously, you’re not always at home as and when your baby needs a bottle. Keeping things hygienic is equally important when you are on the move. Lesley from MyExpertMidwife has some suggestions: “The two most portable methods are the cold-water chemicals (tablets or liquid), and the microwave steam sterilizer. The beauty of the tablets/liquid is that you can safely pack them away in a case for foreign holidays or slip them into your handbag if just out for the day. Remember, you will still need access to cold water and a lidded unit deep enough to fully submerge the equipment.”

You can opt for steam sterilizing if you are at a friend or relative’s home and they have a microwave, or if you are away and can access a microwave. Lesley explains,“A steam sterilizer is normally highly portable due to its small size so can fit in a bag and just needs water and a microwave – but check before you go that there is a microwave and that you are allowed to use a sterilizer in it. Or you could sterilize some bottles at home, fit the teats and lids (adhering to sterile technique), keep them in a bag until you need them, and use within 24 hours – being absolutely stringent when adding the formula or breast milk to avoid contamination.”

For more information about sterilizing, you can speak to your midwife or health visitor, contact the manufacturer of your sterilizing equipment, or visit UNICEF.

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Jo Dunbar

Jo is a freelance journalist, writing for newspapers, magazines and websites such as Good Housekeeping, Grazia, Mother & Baby, The Daily Telegraph, Daily Express, Daily Mirror, Bella, Yours and Woman&Home. Jo started out in entertainment journalism and has scurried up plenty of red carpets and interviewed stars such as Joan Collins, Dawn French, Jane Fonda and Julie Walters. These days, she mainly covers health, parenting, lifestyle and consumer news but is always keen to vent in an opinion piece or dust off her schmoozing skills and interview a celeb. When not writing (and reading) Jo loves to get outside, wear out her two sons on a beach, drink good coffee and expand her baking repertoire.