Can you use a dishwasher instead of a steriliser?

It’s important to thoroughly wash and sterilise baby bottles and other baby feeding equipment before using them¹, to help protect your baby from infections. So, is it safe to use a high-temp dishwasher cycle to do that job?

With the help of expert microbiologists Dr Sharad Kamble and Dr Helen Onyeaka, and expert bacteriologist Dr Zina Alfahl, we have the answers…

The takeaway expert advice

A dishwasher can clean baby bottles and feeding equipment but it cannot sterilise them.

So this means that, even if you use a dishwasher first:

• You will still need sterilise bottles, teats and other bottle-feeding equipment until your baby is 12 months old.
• You will need to sterilise your child’s dummy until they are 6 months old.
• You don’t need to sterilise weaning equipment (bowls, plates, spoons) if you’re weaning your baby at the recommended age of 6 months but, if you’re weaning your baby between 4 and 6 months, you’ll need to sterilise weaning equipment until your baby is 6 months old.

Can I put baby bottles, rings and teats in the dishwasher?

Yes, you can put baby bottles in the dishwasher to clean them – instead of hand-washing them in hot, soapy water. But this will only clean them and sanitise them; it will not sterilise them.

“Dishwashers are useful for cleaning but they do not sterilise baby bottles,” confirms Dr Sharad Kamble, a microbiologist at the University of Bradford and a member of Applied Microbiology International’s Food Security Scientific Advisory Group.

So, until your child is 12 months old, you will need to sterilise all this bottle-feeding equipment after it’s been in the dishwasher, either by using a steam steriliser, immersing them in a cold-water sterilising solution for at least 30 minutes, or by boiling them for at least 10 minutes.

Once your baby is 12 months old, and their immune system has developed enough to make them less susceptible to infection, you can skip the sterilising stage.

How to safely wash baby bottles in the dishwasher

• Separate all the bottle parts and remove all traces of milk using a bottle brush
• Stack each part face down in the top rack of the dishwasher, to avoid stray bits of food or dirty water falling into them.
• Avoid putting bottles and teats in the dishwasher with crockery or utensils dirtied with strong-coloured or oily food, as the colour and residue from the food can transfer to the bottles and teats, leaving them discoloured.
• Run a regular programme (between 55°C and 65°C) rather than a cooler eco wash or a hotter wash as many bottles and teats are only dishwasher-safe to 65°C.

Why doesn’t a dishwasher sterilise baby bottles?

To sterilise an item in hot water, it has to be boiled at 100°C for a minimum of 10 minutes.² The water in most dishwashers, even on a hot wash, doesn’t actually reach this temperature.

“Dishwashers typically reach temperatures around 65.5°C to 70°C, with a rinse cycle up to 82°C, ” says Dr Helen Onyeaka, an industrial microbiologist and associate professor in the department of chemical engineering at the University of Birmingham. “This is sufficient for sanitising but not for sterilisation.”

And this is the key point: sanitising a baby bottle is not the same as sterilising it.

“Sanitisation reduces bacteria to a safe level but it does not eradicate them all,” says Dr Onyeaka. “Sterilisation aims to eliminate all forms of bacteria and microorganisms.”

“Microbes can grow very quickly on tiny traces of milk left in bottles,” adds Dr Sharad, “and certain kinds of bacterial spores are prone to surviving dishwasher cycles. The sterilisation process, however, kills all live forms of micro-organisms— including the spores.”

Can I put my child’s dummy in the dishwasher?

It depends on the brand. Some manufacturers, including NUK and MAM, say no because the dishwasher detergent is too abrasive and can damage the dummy, causing it to become brittle. Others — including Tommee Tippee — say their dummies or soothers are dishwasher-safe, as long as they’re put on the top shelf only.

If your child is under 6 months old, whether you wash your child’s dummy in a dishwasher or by hand, you’ll need to sterilise the dummy afterwards, using a method recommended by the manufacturer.

Can I put baby weaning bowls and spoons in the dishwasher?

Yes – and assuming that your weaning baby is 6 months or older, you don’t need to sterilise weaning bowls and spoons afterwards.

However, if, on the advice of your health visitor or GP, you are weaning early (between 4 and 6 months), you will need to sterilise all weaning equipment after it’s been in the dishwasher until your baby is 6 months old.

Why is the age limit different for sterilising bottles than it is for weaning equipment and dummies?

First of all, there are few ‘hiding places’ for microbes on weaning equipment. “Microbes can easily be washed off spoons and bowls as, compared to bottles and particularly teats, there are no difficult-to-reach surfaces where bacterial spores can lurk,” say Dr Sharad.

And weaning bowls and spoons don’t have as much or as frequent ‘mouth contact’ with your baby as bottles do.

“Bottles, heavily used for feeding during the first year, pose a higher risk of bacterial contamination,” says Dr Zina Alfahl, postdoctoral researcher in bacteriology at the University of Galway and a member of AMI’s One Health Advisory Group. “That’s because they have direct and prolonged contact with your baby’s mouth and with the milk.”

“Weaning equipment encounters less oral contact and has reduced risk of contamination from food, making frequent sterilisation less necessary.”

Please note: The NHS advice on sterilising baby bottles that’s given to UK parents – and explained here – is different to the advice to US parents by the Centers for Disease Control and Prevention.

Additional research by Gabrielle Nathan. 

References

1. Sterilising baby bottles. NHS online

2. Steam sterilisation. Infection Control, Centers for Disease Control and Prevention.

This article has been reproduced with kind permission of Made for Mums.