When it comes to your baby’s health, keeping feeding equipment clean and safe is a top priority. Whether you're bottle feeding with formula, expressed breast milk, or a combination of both, sterilising baby bottles is essential to protect your little one from germs, bacteria and infections.
In this guide, we’ll walk you through why sterilising is important, how to do it properly, the different methods available, and what the NHS recommends - so you can feel confident about every feed.
Why Is Sterilising Baby Bottles Important?
Babies under 12 months have developing immune systems, which makes them more vulnerable to illness. Bottles, teats, and pump parts can easily harbour bacteria - even after washing with soap and water.
Sterilising kills harmful germs that may be left behind after cleaning. It’s especially important when using:
- Infant formula (which isn’t sterile even when sealed)
- Expressed breast milk, particularly for premature or ill babies
- Shared feeding equipment (e.g., at childcare or with other carers)
When Should You Sterilise?
You should sterilise:
- Before every feed during the first 12 months
- After every use of bottles, teats, and pump parts
- After items have been dropped on the floor or contaminated
- If bottles are used after 24 hours without re-sterilising
What Needs to Be Sterilised?
- Baby bottles and teats
- Bottle caps, rings, and lids
- Breast pump parts that come into contact with milk
- Milk storage containers
- Dummies (if used)
Step-by-Step: How to Clean and Sterilise Bottles
Before sterilising, always wash everything thoroughly:
Step 1: Wash
- Rinse bottles and teats under running water
- Use warm soapy water and a dedicated bottle brush
- Rinse again with clean water
Don’t skip this step - sterilisers won’t work properly on dirty equipment.
Step 2: Choose a Sterilising Method
1. Cold Water Sterilising
- Use a sterilising solution or tablet in cold water
- Fully submerge all parts, making sure there are no air bubbles
- Leave for at least 30 minutes
- Change solution every 24 hours
2. Steam Sterilising (Electric or Microwave)
- Follow the instructions on your steriliser
- Add the right amount of water
- Run cycle (usually 5–10 minutes)
- Leave bottles in the closed unit until needed (usually sterile for 24 hours)
3. Boiling
- Place items in a pan of boiling water for at least 10 minutes
- Ensure everything stays fully submerged
- Use tongs to remove items carefully
How to Store Sterilised Bottles
- Use bottles immediately if possible
- If storing, keep them sealed and assembled to prevent contamination
- Store in a clean container or in the steriliser with lid closed
- Sterile bottles stay safe for up to 24 hours if untouched
What About Breast Pumps?
Your pump parts should be sterilised after each use. This includes:
- Breast shields
- Valves and membranes
- Milk collection containers
- Tubing (if it comes into contact with milk)
When Can I Stop Sterilising?
The NHS recommends sterilising all baby feeding equipment until your baby is 12 months old, regardless of whether you're feeding formula or expressed milk.
After that, you can wash items in hot, soapy water or a dishwasher - but continue sterilising if your child is premature, has health conditions, or your healthcare professional advises it.
Midwife’s Top Tips
- Always clean bottles first - sterilising isn’t a substitute for washing
- Keep a spare set of bottles ready if you’re out for the day
- Microwave steam bags are great for travel or office use
- Replace teats regularly - they wear down with use and sterilising
- Avoid touching inside bottles or teats after sterilising - use tongs if needed
Sterilising might feel like just another chore but it’s a simple way to protect your baby’s health and feeding experience.
