What to do if Baby Bottle has Mold – (5 Tips) on How to Fix the Problem

Balint Horvath, PhD

Writer, parent, and veteran of baby feeding battles.


You want to keep your baby as safe and healthy as possible. You clean, tidy, wipe, wash and sterilize from dawn to dusk. And then all of a sudden you see a baby bottle that has mold in it. So what can you do if your baby’s bottle has mold in it

You won’t necessarily have to trash the bottle. While mold is serious, there are some steps you can take to eradicate the problem without taking drastic action. So, don’t throw away those moldy bottles yet. 

Key takeaways

  • Mold can cause serious health issues
  • Mold forms in humid environments
  • Not washing, drying, or sterilizing baby’s bottles can lead to mold forming
  • Wash each part of the bottle and teat well
  • Sterilize bottles and teats regularly
  • Throw away bottles or teats with cracks in 
  • Dry bottles and teats thoroughly
  • Store separately

What is Mold and What are the Signs of Mold?

Mold is a fungal growth that grows in moist environments. There are many forms and colors of mold. Additionally, mold grows in multicellular structures. Those structures are called hyphae and produce spores that spread through the air, and those spores cause health problems in humans. It’s sometimes also called mildew. 

If you notice a furry growth or something that looks like a black stain in the bottle, it’s likely to be mold. What’s more, mold can have an orange, green, white, or brown color. 

What causes mold growth in baby bottles? 

There are a number of factors that cause mold to grow in your baby’s bottle. They are linked to a moist environment, which mold enjoys and expands within. Here are some common causes of mold growth in baby bottles. 

Not washing bottles properly 

First and foremost, if you don’t wash your bottles properly, they may develop mold. You must wash bottles in boiling water, or sterilize them with a baby sterilizer. They must also be washed in every crack and crevice, particularly the teats.

Not drying the bottles properly 

If you don’t dry the bottles thoroughly, because, for example, you decided you don’t need a bottle drying rack, then moisture remains in parts of the bottle. Mold loves such environments, and can quickly start forming before you even notice it. You must dry bottles and teats on a drying rack, or, on a paper towel where moisture is drawn away from the items in question. 

You need to sterilize your bottles regularly. You can boil them in hot water for 10 minutes, steam them, or microwave them. You can also use a sterilizing solution in cold water.

What happens if a baby drinks out of a moldy bottle? 

Not all mold is toxic. However, mold can cause allergies such as hay fever, asthma, and sinusitis, and lead to bronchitis. Some mold, however, is toxic, and your baby can develop an upset stomach or diarrhea

It can also cause a stuffy nose, irritation in the eyes, skin irritation, and wheezing. In immunocompromised people, you can get mold infections in the lung. So, all in all, it’s best to avoid mold altogether. 

Your doctor may not be able to pick up that the cause of these symptoms is mold, so you need to examine all bottles, teats, and lids very carefully before any doctor’s visit.

How to prevent mold growth in baby bottles

You can prevent mold in baby bottles by cleaning, drying, and sterilizing them thoroughly. It’s only in certain cases that you have to throw the bottle out. 

You can also watch this video below on how to clean baby bottles properly.

When you put a pre-made bottle in the fridge, make sure you don’t leave it in there for too long – this is another way to prevent mold growth.

If you have mold already here’s what you can do.

Firstly though, check the bottle and nipple and decide if something should be thrown away. If there are cracks anywhere, then mold can form in there without you being able to get to it. Discard those parts. Rather the cost of a new bottle or teats than many doctor’s visits and an unhappy, unhealthy child. 

Secondly, scrape the mold off any surface. Be careful with the nipple – you don’t want to cause cracks or crevices in it. It’s best not to use the sharp end of a knife there. Rather use a rounded plastic or metal surface to do so, like a pot-scraper. 

Wash bottles immediately after use

It’s best not to leave liquids such as milk or tea in bottles. It’s just the sort of humid environment that mold thrives in. Instead, throw out the rest of the liquid, if any, and wash straight away. If you also dry it thoroughly, then you have a very low chance of any mold forming in the bottles. 

Wash with hot soapy water before sterilizing. You must get rid of the black, white, green, or orange color completely, and then you sterilize it using your regular method of sterilization. Another point is to ensure that baby bottle brushes are hygienic and work well too.

In severe cases of mold growth, rinse with vinegar before washing

If you don’t get rid of the mold, or if the mold growth is already quite advanced, then you have to use a solution of equal parts water and vinegar. Wash out the bottles, lids, and teats in this solution. Turn the teat inside out in order to get the part that you normally couldn’t reach, and wash that too. 

Please note that it’s important to wash moldy bottles or teats separately from other bottles or teats. You don’t want one to contaminate the other in any way. So, it’s best to wash unaffected bottles first before contemplating washing moldy ones. 

Clean bottles with warm soapy water 

Bottles then need to be cleaned with warm soapy water. make sure it’s as hot as you can make it. Your regular dishwasher soap is mild enough for the bottle and for the baby. Besides this, you will rinse it with hot water until there is no soap left. Set it out to dry immediately. 

Sterilize bottles regularly

Once you have washed your bottles, you need to keep up a strict regimen of sterilizing your bottles and nipples. You can use a sterilizing solution (for example bleach) mixed with water to soak your bottles in for about 20 minutes. Or you can boil them in a pot for 10 minutes. You can also put them in the microwave for 1 minute – either in a microwave sterilizer or on their own. Another great solution is washing the bottles with baby shampoo which is less harsh than regular dishwashing soap.

Just make sure you dry them thoroughly afterward. You also need to know how often to change baby bottles and nipples to avoid so your baby always has a fresh bottle.

Allow bottles and nipples to air dry thoroughly

Dry the bottles thoroughly after sterilizing or washing them. Leave them to dry on a separate rack, or place them on a paper towel to draw out the moisture. Make sure not a drop of moisture is left before you put them away in storage. 

Make sure the lids are tight, not allowing outside air, with pores or bacteria, to come inside. You can in fact keep them in the sterilizer until it’s time to use them.

Another solution – enter the world of bottle liners

You may also consider using disposable bottle liners, especially when you’re traveling and you don’t have access to water for cleaning your bottle. By ensuring that contact to milk happens only for the bottle liner which you throw away after use, you neatly prevent the build-up of mold. No water, no mold. 🙂

Photo of author


I’m Balint, founder of this site and a father (and dad) to a baby-turned toddler. I found the world of babies so fascinating that I started a blog dedicated only to that topic. By the way, I studied physics, engineering (PhD, MSc), and therefore I do a thorough research when I write about something. Since it’s a blog, of course I also write about my personal experiences.

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