My wife asked me, “how often should I sterilize baby bottles?” around a few months ago. For us, we tend to sterilize our baby bottles around once a month. Sometimes, when I have time, I do it around once every two weeks. There are usually no set rules we decide on. Quite often I try not to sterilize our baby bottles if I can help it. There are very good reasons for that too. These reasons are for the sake of our baby daughter also. One of the main reason is because baby bottles are made of plastic.

Sterilizing Usually Involves Heat

More often than not, sterilizing your bottles involves some kind of heat whether it is using the regular boiling method or the microwave steam method I mentioned in my other article. If you do this occasionally, then everything would be alright. However, if you sterilize your bottles on a daily basis, the plastic will begin to melt and change shape.

An example of that is shown in this Youtube video:

When a baby bottle changes shape, it is also no longer leak proof. This has actually happened to a Dr. Brown bottle I have used before. At one point, we sterilized religiously everyday. Within a month, we noticed that the bottle started leaking when my daughter is drinking milk. In other words over sterilizing your bottles can compromise the integrity of the bottle and make it leak.

Of course, this doesn’t apply if you use the hydrogen peroxide method I mentioned where you thoroughly rinse the peroxide back out. However, that is a very expensive option, and it takes some work to rinse the solution back out. This method doesn’t mutate your bottles, but it will eventually thin out your wallet.

Highly Recommended Alternate Options To Sterilizing

Instead of sterilizing your baby bottles all the time, you should simply clean them instead. Usually, any doctor you talk to will recommend you simply use warm water and soap, and you are good to go.

Just make sure you use a bottle and nipple brush to thoroughly brush all the parts of your bottle. Leaving milk residue behind is the same as creating a germ factory. This is especially true if you are using a dishwasher. You must clean out all milk residues before you dump your bottles in.

Another thing I have to point out is to clean out your baby bottles milk residues immediately after she finishes her milk.

The bacteria from your baby’s mouth has already thoroughly contaminated it. After you finish washing, get a clean rack and let it drip dry to remove soap residue and water.

If you want a healthy soap option then try Dr. Bronner’s soaps as I mentioned in my other article about baby friendly detergents. This soap is so versatile, you can use it to clean anything in the house, and that includes food.

Also make sure your bottle brush and nipple brush remains clean and dry when you are not using them. Hang them somewhere instead of just laying them around on a table top. From time to time, if you are sterilizing your bottles, swirl your brushes quickly in boiling water (if you are using this method) to clean it up a bit, even though that is not really necessary.

What About Glass Bottles?

You might think that it will be alright to sterilize your bottles as long they are made of glass. The reason is because household boiling water can not alter the shape of glass after all.

You are half right. However, the nipples, and the caps are still made of plastic and silicone. In the end, you will still half of your bottle equipment “sterilized”. Besides, no matter what sterilization technique you use, your baby bottles are never truly sterilized.

It Is Not Really Possible To Use Sterilized Bottles 

By definition, sterilization means that all life forms (referring to germs) are dead. It is true that after you boiled your bottles for three minutes, the bottles are sterile while being inside that boiling water. However, the moment you take it out, it becomes contaminated even if the contamination is very small.

This can’t be helped. There are germs everywhere. There are germs:

  • In the air you breath
  • In the objects you touch
  • In the water you drink
  • Even in the yogurt you eat

You Should Still Sterilize New Bottles

Even though it is true that your bottles are not sterile the moment you make contact with them, you should definitely still sterilize them after un-boxing new ones. New bottles might contain a lot of germs, dust, and whatever chemicals and was resin that was used to make them. Using the boiling method definitely flushes out most of the harmful stuff.

You Should Sterilize If Your Water Is Compromised

If you live where I live, the tap water is often very clean so sterilizing is usually not necessary. However, if you live in an area where your water source is often contaminated, like a water well or a river for example, then that is a different story. For your case, you should sterilize your bottles after each use so your baby doesn’t get sick.

Another situation in which you should sterilize your bottles after every use is if your baby has a yeast infection. This also applies if your baby has yeast infection (like oral thrush for example). In the case of an infection, even teethers and pacifiers have to be sterilized after each use.

Of course, for your situation, it is a given that you will have to replace your bottles more often unless you are using glass.

Theoretically, you can stop sterilizing your bottles after your baby reaches 12 months of age. At the point, your baby most likely has a well built immune system that can resist pathogens on its own.

What About Breast Pump Parts?

Just like baby bottles, sterilize them based on your circumstances. If you have a contaminated water source then it is necessary to sterilize after every use.

Other than those situations, simply cleaning them thoroughly is fine. Just bottles, it is not possible to keep them sterile all the time.

Germ Free Doesn’t Mean It Is Better

I know some parents that has an extreme fear of germs. Everything they use has to be completely clean before they use it. While I agree that being a slob, which is the opposite extreme, isn’t a better option, I don’t personally agree with being overly clean either.

As mentioned earlier, there’s no such thing as a truly sterile environment, unless you nuke everything with a toxic gas that kills all living matter. In that situation, everybody will die along with the germs, which is not what you want.

Besides, even if it is possible to only eliminate the germs (or microbes in general) in the environment you live in, it is not your healthiest option either.

Scientists has attempted an experiment in which a newly born sterile mouse is immediately moved to live in an isolated sterile environment. Can you guess what the results were?

Life Of A Sterile Mouse

A mouse that is born and lives sterile had a lot of problems. Almost every organ of the sterile mouse is smaller, and less robust in strength. The immune system of a sterile mouse is also a lot weaker than a regular mouse.

The most important thing is that sterile mice are weak against stress. If you give them shock and stress, they are less likely to be able to handle it compared to regular mice.

If your baby lived as a sterile human, there’s very little chance that she will be able to handle herself in the future as she grows up, because you and I both know that society has plenty of stress waiting for her.

Humans and Good Germs Help Each Other

We are evolved to live along with microbes and support each other. Probiotic, are beneficial microbes, or good germs that has been living with us for a very long time. We relied on them, and they relied on us for survival.

Of course, they have been in existence much longer than we have. They don’t really need to rely on us, but we definitely benefit from having them in our system.

They keep us healthy by helping with digestion, blocking out harmful germs, and producing nutrients like vitamin B12 for example. These good germs can often be replenished by taking in a good source of probiotics with live culture like:

  • Kefir
  • Kombucha
  • Yogurt

With good germs in our system as backup, small amounts of harmful germs would be perfect training for our baby’s immune system to defend against. Just don’t introduce too many germs and overwhelm the baby of course (like handling bottles without washing your hands for example) which will leads to infection and diseases.

Instead, Think Of Changing Broken Bottle Parts

As I mentioned earlier, if you wash and clean your baby bottles after every feeding then you should do fine as long your water source is not contaminated. However, even though your bottles can be used safely, you should still change your bottle parts once they are about to break.

This usually applies to the bottle nipples you use. They are the weakest part of your bottle considering how soft they are. Every time your baby sucks on them, and you boil them, they get weaker and must be replaced. Of course, you can wait till they show signs of wear and tear before you throw them away.

Signs of Broken Bottle Nipples

If your bottle nipples shows the following problems then throw it out and replace them:

  • Milk sprays out instead of dripping out in a controlled flow
  • The bottle nipple turns darker or changes color
  • You notice cracks and a bigger hole in the bottle nipple
  • Your bottle nipple has no rebound strength (pull it and let go. If it doesn’t go back to original shape quickly then it is no longer good)
  • The bottle nipple looks thinner
  • The bottle nipple has a slimy and sticky texture
  • Part of the bottle nipple looks swollen and slightly inflated


If the area you live in has good source of clean tap water, then you should definitely not sterilize your bottles too often. If you are like me, you can sterilize them once a month if you want. However, you technically don’t have to sterilize them unless they freshly un-boxed.

For those who live in contaminated areas, sterilizing is mandatory for you until your baby is roughly 12 months of age. Just double check with pediatrician to be sure that it is healthy to do so.

Remember to replace your bottle parts when they are overused. I hope this article was helpful to parents who are confused about this. If you have any questions, please leave it in the comment section below.