Sterilising Baby Equipment: FAQs for New Parents

Samantha Pieterse
Jan 30, 2024
8 min read

Updated: May 23

This is a question I'm asked frequently, and something I, too, wondered as a new mother. We all know that as parents, we want to do everything possible to keep our little ones safe and healthy. Sterilising baby equipment and bottles plays a super important role in this. This is why I did a quick FAQ on the ins and outs of sterilizing the equipment.

Blue, green and yellow bottles drying on a bottle dry rack.

FAQs On Sterilising Baby Equipment

Why Do We Sterilise Bottles and Baby Equipment?

In the first few months of life, your baby’s immune system is still learning to defend your baby against infection. Their body hasn’t yet built the antibodies and natural defences that help fight off everyday bugs. That’s why sterilising feeding equipment is especially important in the first 8 weeks.

Anything that goes into your baby’s mouth, bottles, dummies, breast pump parts, or even teething toys can carry bacteria, viruses, or fungal spores. And while these might not be a big deal for older children or adults, in young babies, they can cause serious infections.

What Can Happen If My Baby’s Feeding Equipment Isn’t Sterilised?

The most common problems are gastrointestinal infections, such as diarrhea and vomiting. These can lead to dehydration very quickly in tiny babies, especially those under two months, and in severe cases, might require hospital care. In rare cases, harmful bacteria like E. coli or Salmonella can contaminate bottles and cause more serious illnesses.

Babies born prematurely or with underlying health issues are even more at risk, which is why sterilizing is important to protect your newborn in those early weeks.

Once your baby is around 2 to 3 months old, their immune system becomes more mature, and their gut develops healthy bacteria that help fight off pathogens. At this stage, sterilising becomes less important, but many parents choose to continue through the first year as an added layer of protection.

It’s also helpful to keep sterilising if your baby has been sick, has thrush or if you’re in an environment where clean water and hygiene are harder to maintain, such as when travelling or during load shedding, when hot water might not be consistently available.

So while it may feel like a bit of a mission in the early days, sterilising is a simple step you can take to help keep your baby healthy.

What Are the Different Ways to Sterilise Bottles and Equipment?

There are several safe and effective ways to sterilise baby bottles, teats, dummies, breast pump parts, and feeding spoons. The best method depends on your lifestyle and how often you’re using your feeding equipment.

Before we get into the how, here’s a quick reminder: Sterilising is not the same as cleaning.

Before sterilising, wash all equipment thoroughly in warm, soapy water or the dishwasher. This removes leftover milk or formula because bacteria love to grow on even the tiniest bits of residue. Sterilisation comes after cleaning. Its job is to kill the remaining germs. Now let’s look at your options:

1. Steam Sterilising (Microwave or Electric)

This is one of the most popular and convenient methods.

How it works: Place clean bottles and equipment into a steriliser with a bit of water. The heat turns the water into steam, which kills bacteria, viruses, and fungi due to its high temperature.

Microwave sterilizers are compact and fast, typically taking 2–8 minutes. Just make sure your equipment is microwave-safe. Electric sterilisers often have timers and drying functions.

Pros: Fast, easy, and chemical-free.

Watch out for: Steam can be very hot, so always open the lid away from your face.

Tip: Keep the steriliser clean, too. Mold can build up if it stays damp and closed for long periods.

2. Boiling

The classic method, and still one of the most effective.

How it works: Submerge bottles and parts in a large pot of boiling water for at least 5 minutes at a rolling boil. Remove them with tongs and place them on a clean, dry rack (or leave them in the pot with the lid on).

Pros: Cost-effective and doesn't require special equipment.

Watch out for: Some plastic items can warp with frequent boiling. Always check the manufacturer’s guidelines.

3. Cold Sterilising (e.g., Milton or Similar)

This method uses a chemical sterilising solution dissolved in cold water.

How it works: Place items in the solution and let them soak for at least 15 minutes (up to 24 hours). The solution is reusable for 24 hours, so you can add items as needed throughout the day.

Pros: Handy when you’re travelling or don’t have access to electricity.

Watch out for: Cold sterilising chemicals can leave a taste or smell on bottles if not rinsed properly, and they may kill some beneficial bacteria in your baby’s mouth and gut. Use with caution and avoid overuse.

4. Dishwasher (Only for Certain Items)

Some bottles and parts can be placed directly into the dishwasher, ideally on the hottest cycle with a heated drying function.

Pros: Convenient for families already using a dishwasher daily.

Watch out for: Not all baby equipment is dishwasher-safe, and dishwashers don’t always sterilise completely, especially if the water doesn't reach high enough temperatures. Consider this more of a deep clean than a full sterilize.

Is One Method Better Than Another for Sterilising Bottles and Baby Gear?

When it comes to killing harmful bacteria, viruses, and fungi, all common sterilising methods like steam, boiling, and chemical (cold water) solutions are effective when used correctly. So on a basic hygiene level, you can choose whichever method works best for your family’s routine and resources.

But there's a bit more to the story.

While cold water chemical sterilising solutions (like Milton) are convenient and great for travel or emergencies, they have a slight downside: they can affect more than just the harmful bacteria. These solutions don’t discriminate; they may also kill off some of the beneficial bacteria your baby needs for healthy digestion and a strong immune system, especially in their mouth and gut.

This delicate balance of good bacteria, known as the microbiome, plays a growing role in our understanding of infant health. Disrupting it too often, especially in the early months, may increase the risk of oral thrush, nappy rash, or even longer-term issues like food sensitivities and digestive discomfort.

That’s why I usually recommend:

Steam sterilising (microwave or electric) as your go-to for everyday use
Boiling if you don’t have a steriliser or want a simple, low-cost option
Cold water sterilising as a backup for travel, power outages, or when you need to sterilise something quickly and don’t have access to heat

The bottom line: use what works, but aim for heat when possible. It’s effective, chemical-free, and gentler on the good bacteria your baby’s body is working hard to grow.

Is it Necessary to Sterilise Baby Equipment After Each Use?

Short answer: not always, but in some situations, it’s recommended.

During your baby’s first 3 months, their immune system is still immature, and the risk of infections from bacteria is higher. So yes, during this stage, it’s best to sterilise bottles and feeding equipment more frequently, ideally after every use, or 2–3 times a day if that’s more realistic for your routine.

Once your baby is past the 12-week mark and generally healthy, you can usually relax a little. At this stage:

Washing bottles and teats thoroughly in hot, soapy water right after each feed goes a long way in keeping them safe.
You can then sterilise once a day, and that’s typically sufficient for babies with a stronger immune system.

Dishwashers can help, too. A hot rinse cycle (above 65°C) will clean and partly sterilise, but you’ll still need to manually sterilise items now and then to be safe.

At What Age is it No Longer Necessary to Sterilise Baby Bottles and Equipment?

Most health guidelines recommend that you continue sterilising baby bottles and feeding equipment until your baby is at least 12 months old. That’s because by around a year, your baby’s immune system has matured significantly, and they’re eating solids (read: putting dirty things from the floor in their mouth). Their gut is better equipped to handle common bacteria.

That said, it doesn’t mean you must sterilise after every use for a whole year. Here's a breakdown:

0–3 Months:

Sterilise after every use (or at least 2–3 times daily). Your baby’s immune system is still immature and highly susceptible to tummy bugs and infections.

3–6 Months:

Sterilising once daily is usually fine, as long as bottles are washed promptly after each feed. You can keep sterilising with steaming, boiling, or cold water.

6–12 Months:

By now, your baby is starting solids, chewing on toys, and building more immunity. You can begin to phase out sterilising, especially if your baby is healthy and growing well. However, if your little one has been sick, has a compromised immune system, or uses formula, it's still a good idea to continue.

What About the Dishwasher?

If you’ve got a dishwasher with a hot wash and heated dry setting, many bottles and teats can be washed that way instead of sterilising daily. Make sure the items are labelled dishwasher-safe, and use the longest, hottest cycle (above 65°C) to kill bacteria.

⚠️ Situations Where You Should Keep Sterilising Longer:

Your baby was born prematurely or has certain health conditions
You don’t have consistent access to clean running water or electricity
You’re feeding expressed breast milk or formula and want to reduce the risk of contamination
Your baby has had recurrent infections, especially oral thrush or gastro

The bottom line is that if your baby is healthy, you can begin to ease up after 6 months and stop sterilising entirely by around 12 months, although safe, thorough cleaning is still non-negotiable.

After Sterilising a Bottle, How Long Does It Stay Sterile?

Once a bottle or piece of feeding equipment has been properly sterilised, it will stay sterile for up to 24 hours but only if it’s stored and handled correctly afterward.

That means the moment you touch the inside of the bottle, the teat, or any surface that will come into contact with milk or your baby’s mouth, the sterile status is lost.

To keep bottles sterile after sterilising:

Avoid touching the inside of the bottle or the teat. Hold bottles by the base or neck ring, and teats by the outer rim or plastic screw cap.
Let them air dry in a clean space, don’t wipe with a cloth or towel, as that can introduce new bacteria.
Store bottles upside down, so no moisture collects inside and the open end is protected from airborne germs.

Where should you store sterilised bottles?

The best place is a clean, sealable container, either glass or BPA-free plastic. If possible, keep it in the fridge to slow down any bacterial growth (especially helpful in summer or during load shedding when room temps can climb). Freezing isn't usually necessary unless you’re also storing expressed breastmilk in the same container.

And if you're using a steriliser with a built-in lid (like some electric models), you can often leave bottles in there until you're ready to use them, just be sure to open it as little as possible to keep the inside environment clean.

Final Thoughts on Sterilising Bottles

If you’re reading this, chances are you’re already doing a great job. Sterilising can feel like yet another thing to remember, but it’s one of those small things that helps keep your baby safe while their immune system gets stronger.

And if you haven’t been perfect with sterilising, don’t panic none of us do everything perfectly all of the time. It’s never too late to start, and a little effort goes a long way.