I've read different things online about this.

I pump breastmilk to feed to my little one. I'm currently boiling the pump bottle and the feeding bottle everyday at the start of the day, but if I use the same bottle through the day for breastmilk, do I need to sterilize it by boiling again? My little one is 1 month old.

I dump the milk from the pump bottle into the feeding bottle because baby likes it better.


4 Answers 4


See WebMD:

In the old days when water supplies were not reliably clean, it made sense to sterilize baby bottles. But now, sterilizing bottles, nipples, and water is mostly unnecessary.

Unless your water supply is suspected to harbor contaminated bacteria, it is as safe for your baby as it is for you. There is no reason to sterilize what is already safe.

In fact, if you sterilize everything around your baby all the time, many believe it could increase likelihood of becoming allergic.

I recommend that you clean your bottles with a dish-brush because there are areas within a bottle that can't be cleaned effectively by a washing machine (resulting in massive bacteria buildup).

  • There are also soaps designed to better break down milk for cleaning bottles. We never used them except when given as gifts, but they exist. We only boiled bottles and pump parts once a month or less, for good cleaning (especially after the little guy had an illness)
    – user11394
    Commented Sep 24, 2015 at 3:47

As explained by Gruber's answer, sterilizing the bottles is usually completely unnecessary.

However, there is a risk of buildup of harmful germs if the bottles are left to stand for too long with (rests of) milk inside. So while sterilizing is probably not required, you should wash them regularly and thoroughly, and refrigerate the milk as soon as possible.

The recommendations I know are:

  • Use a fresh (i.e. washed) bottle/container everytime you pump, and put it into the fridge immediately after pumping (unless you feed right away). If you keep using the same container, there is a risk the old milk from previous pumpings will be kept at room temperature for too long. You can pour the freshly pumped milk into the container in the fridge, if the milk is not older than a day - just use a fresh container during pumping.
  • When feeding your child, only take as much milk from the fridge as you need, and warm it up. If the child does not drink everything, it is best to discard the rest after a few hours, as it has been warm for too long.
  • Store breast milk refridgerated if possible. Medela (a pump manufacturer) recommends the following maximum storage times:
    • room temperature: 4-6h
    • fridge: 3-8 days
    • freezers: 6-12 months. After thawing, keep in fridge for max. 10h.

Some old rule I remember some old person telling me was to boil all the stuff in hot water every week but only on saturdays. In my local language saturday is cleaning day. The other days the stuff would just get cleaning like the other dining utensils.

But if the doctor has advised other treatment, than that should be followed.

A way to sanitize sensitive stuff that can not handle the boiling is to use 1 part of Vinegar (4-8% CH3COOH) with 9 parts water -> (0,4-0,8% CH3COOH), and submerge the items for 3 minutes.


As others have said, sterilizing is not necessary as long as you give the bottles a good cleaning in warm water with soap. Make sure that the nipple is cleaned thoroughly. Most manufacturers recommend in the packaging of their products to sterilize before first use, which is what I did for my kids. It's just to get out any residue from the factory. Otherwise, I never sterilized my kids bottles.

Breast milk stays safe for much longer than formula, so if you are using breast milk you can leave it out for several hours without any harm coming to it. If you do end up using formula (I did for my kids) then you have to be very careful because formula does not last long without becoming harmful, because bacteria build up quickly, so in that case you will need to wash bottles more frequently.

So as a general answer, there is no need to sterilize, just do a good washing in between uses.

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