When and How to Sterilize Baby Bottles (Hint: You Don’t Need to Do It as Often as You Think)

how to sterilize baby bottles

Ever heard the expression that every baby comes with a loaf of bread under his arm? Well, in terms of the joy they bring, that’s true. But there’s no sweet saying that warns new and expecting mothers about the boatload of gear that their bundles of joy will bring—including diapers, bouncy seats, swaddles...and bottles. Whether you choose to breastfeed, formula feed or do a combination of both, there’s a good chance you’ll be filling and then washing many a bottle over the months to come as you care for your babe. The washing part is pretty straightforward (albeit a total pain), but what’s this business about sterilizing? We consulted the experts and got all the information you need on how to sterilize baby bottles, and when you shouldn’t even bother.

Why should I sterilize baby bottles?

Bottle sterilization was a pretty big deal for previous generations of parents (which is why your mother-in-law might be such a noodge about it), but really the practice harkens back to a time when water supplies were questionable in terms of contamination levels. The problem isn’t as significant today and—aside from a few notable and tragic exceptions—most municipal water is safe and clean enough to just wash bottles between feeds and skip the sterilizing step, says the American Academy of Pediatrics. That said, there are some scenarios that call for bottle sterilization, so it’s still important to know how to go about it when the inconvenience arises. Before we get into the how-to, let’s take a look at the situations where it’s advisable to sterilize baby bottles.

1. When your bottles are brand new

“It is important to sterilize bottles initially to protect from disease-causing bacteria,” says board-certified lactation consultant Leigh Anne O’Connor, IBCLC. Because no matter how clean and green those BPA-free bottles are, they still came from an unknown environment and might carry germs that could put the health of a very young baby at risk. This advice also applies to hand-me-downs—so if, in a previous life, the bottles you have belonged to another baby, sterilize ‘em.

2. If your baby goes to daycare

O’Connor also recommends daily sterilizing of bottles for any baby going to daycare since the daycare setting allows for more contact with more people and there’s the rare (but real) possibility of switching bottles from one baby to another. Germs and illness are inevitable, regardless of whether or not a child attends daycare, but since young babies have less developed immune systems and are more vulnerable to getting seriously sick than their toddler counterparts, it’s best to minimize the risk by sanitizing each bottle you get back from the provider before using it again.

3. For young, premature or immunocompromised babies

Per the Centers for Disease Control and Prevention (CDC), regular washing with hot, soapy water is sufficient for older, healthy babies, but “sanitizing is particularly important when your baby is younger than three months, was born prematurely, or has a weakened immune system.” If your little one meets that criteria, play it safe and sterilize bottles at least once daily.

4. Whenever the water seems sketchy

Municipal water is generally safe and (with soap) will do the trick when it comes to de-germing baby bottles. However, if your particular region has had issues with contaminated tap water, you rely on well water at home or are traveling to another country with unclean water, you should sterilize bottles before use.

Got it. So how do I sterilize baby bottles?

If you bottle-feed your babe, there will be a time (see above) when you need to do more than suds up your supplies. The following sanitizing methods are all equally effective at destroying bacteria and germs that like to hang around on baby bottles, so pick one and rest assured that your little one will be fed from a sterile source. Note: Remember to always wash your hands before handling baby bottles.

How to Sterilize Bottles in the Dishwasher

If you own a dishwasher, you’re in luck: Sanitizing will be a cinch. According to the CDC, “If you use a dishwasher with hot water and a heating drying cycle (or sanitizing setting) to clean infant feeding items, a separate sanitizing step is not necessary.” In other words, pop your baby’s dishwasher-safe bottles in your trusty kitchen helper and they will emerge washed, sterilized, and totally ready to meet the needs of your hungry baby. Here’s what you do.

1. Give used bottles a quick rinse. If the bottles have been sitting around in the sink for a while (no judgment) be extra thorough with this step.
2. Place rinsed bottles in the dishwasher and make sure it is set to run on a hot water wash and heat/sanitize dry cycle.
3. Press ‘Start’ and you’re done. When the dishwasher is done working its magic, the bottles will be good to go.

How to Sterilize Bottles by Boiling

If the only dishwashers in your home are the human kind, don’t fret—sterilizing bottles is actually much easier than scrubbing dinner dishes and it requires no elbow grease. Here’s how to do it, per the CDC.

1. Wash all the parts of the used bottles—nipple, collar, cap, bottle and sometimes a fancy straw—thoroughly with soap and hot water.
2. While the washed bottles hang out in your dish drain, prepare them for sterilizing by filling a stockpot with enough boiling water to completely cover the disassembled bottles.
3. Add the bottles and parts to the pot, dunking the bottles under the water so they are filled and no longer float to the surface.
4. Set the pot on the stove and bring the water to a boil over high heat.
5. Boil the baby bottles for five minutes to sterilize. (Note: The CDC recommends five minutes but the time required may be slightly more or less depending on the material of the bottle—check the packaging insert or manufacturer’s webpage for specific recommendations.)
6. After the recommended boiling time has passed, grab a clean pair of tongs and remove the feeding items from the boiling water. Transfer to a paper towel or clean cloth to cool and dry. 

How to Sterilize Bottles With Steam

The boiling method is so easy that you don’t need to have an electric steaming system to sterilize bottles. But if you happened to be gifted one at your baby shower then, by all means, plug it in and put it to use.

1. Disassemble the used bottles and wash each part thoroughly with soap and hot water.
2. Transfer parts to the electric steaming system.
3. Consult the instructions that came with the product and follow the manufacturer’s recommended procedure. (This usually just means popping the bottles into the device, filling it up with a little bit water and pressing start.)
4. At the end of the process, your fancy baby care appliance will have done its job and those bottles are now ready to see some action.

How to Sanitize Bottles With Bleach

Bleach is an incredibly effective way to sanitize just about anything and will deliver a squeaky clean outcome. Scared to use the stuff on your baby’s bottles? Don’t be. The CDC recommends this method when you can’t boil, steam or use the dishwasher and says that any bleach remaining on the bottles after the sterilization process “will break down quickly as it dries and will not hurt your baby.” Now that we got that out of the way, here’s what the health experts say to do.

1. Again, disassemble and wash bottles with soap and hot water prior to sanitizing.
2. Prepare a sanitizing solution by diluting two teaspoons of bleach with 16 cups (one gallon) of water in a clean bucket or basin. If you’re working with a lot of dirty bottles, you can double the recipe—just don’t mess with the recommended ratio.
3. Submerge the bottles and all their parts in the solution. Sink the bottles to the bottom of the basin to fill them up with water and push air bubbles up to the surface. Squeeze the solution through the rubber nipples and swish around any part that floats to ensure the solution reaches every nook and cranny.
4. Let the bottles and bits soak in the bleach solution for at least two minutes before transferring them to a clean towel to air dry. The CDC advises against rinsing as this could result in recontamination—and because, as previously mentioned, the bleach poses no risk once the bottles have dried.
5. When the bottles have completely dried, they are sterile and safe for use.

Now you know everything you need to know about sterilizing baby bottles, so you’re ready to get started—or happily choose not to in cases where the extra step isn’t indicated.

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Freelance PureWow Editor

Emma Singer is a freelance contributing editor and writer at PureWow who has over 7 years of professional proofreading, copyediting and writing experience. At PureWow, she covers...