Health knowledge and news provided by doctors.

Baby Bottles Release High levels of Microplastics During Formula Prep, Warns Study

Timothy Boyer Ph.D.'s picture
Micro-plastics released from baby bottles could be an health hazard.

A new study warns that many parents are feeding high levels of microplastics from baby bottles to their infants due to incorrect formula preparation. Here’s how you should be doing formula prep to avoid or lessen microplastic exposure.


Infants Are Being Fed Plastic Particles, Shows Study

A new study reveals that high levels of microplastics (MPs) are released from infant-feeding bottles (IFBs) during formula preparation; and, that there is a strong association between the hot water used to sterilize the baby bottles when liquids (including heated formula) come in contact with plastic.

According to the study, a plastic baby bottle made of polypropylene can release millions of microplastic particles and trillions of smaller nano-plastics during typical sterilization in hot water. In fact, they report that significant microplastic release from 0.6 million to 55 million particles per liter occurs even when temperatures are below the boiling point when the temperature of the baby bottle or other types of polypropylene containers are heated between 25 to 95 °C (77 to 203 degrees F).

The key findings of the study determined that:

• PP-IFBs can release up to 16 million MPs and trillions of smaller nanoplastics per liter. Sterilization and exposure to high temperature water significantly increases microplastic release from 0.6 million to 55 million particles/l when temperature increases from 25 to 95 °C.

• Other polypropylene plastic-ware products (kettles, lunchboxes) release similar levels of MPs.

• The team undertook a global survey and estimated the exposure of 12-month-old infants to microplastics in 48 regions. Following current guidelines for infant-feeding bottle sterilization and feeding formula preparation the average daily exposure level for infants is in excess of 1 million MPs. Oceania, North America and Europe have the highest levels of potential exposure, at 2,100,000, 2,280,000, and 2,610,000 particles/day, respectively.

• The level of microplastics released from PP-IFBs can be significantly reduced by following modified sterilization and formula preparation procedures.

The findings were recently published in the journal Nature Food with the authors reporting that although little is known about just how much damage ingesting plastic particles does to an infant’s health, their recommendation is to adopt protective measures to significantly lessen the risk of exposure.

“We have to accept that plastics are pervasive in modern life, and that they release micro and nano-plastics through everyday use. We don’t yet know the risks to human health of these tiny plastic particles, but we can develop behavioral and technological solutions and strategies to mitigate against their exposure,” stated the authors of the study.

Too Much Folic Acid Could Harm Fetal Brain Warns Study

Recommended Solutions for Proper Formula Prep

Sterilizing infant feeding bottles—the authors of the study recommend using the following WHO guidelines towards sterilization of baby bottles.

It is very important that all equipment used for feeding infants and for preparing feeds has been thoroughly cleaned and sterilized before use.

1. Hands should always be washed thoroughly with soap and water before cleaning and sterilizing feeding and preparation equipment (as described below).

2. Cleaning: wash feeding and preparation equipment (e.g. cups, bottles, teats and spoons) thoroughly in hot soapy water. Where feeding bottles are used, clean bottle and teat brushes should be used to scrub inside and outside of bottles and teats to ensure that all remaining feed is removed.

3. After washing the feeding and preparation equipment, rinse thoroughly in safe water.

4. Sterilizing: if using a commercial home sterilizer (e.g. electric or microwave steam sterilizer, or chemical sterilizer), follow manufacturer's instructions. Feeding and preparation equipment can also be sterilized by boiling:

• Fill a large pan with water and completely submerge all washed feeding and preparation equipment, ensuring there are no trapped air bubbles.
• Cover the pan with a lid and bring to a rolling boil, making sure the pan does not boil dry.
• Keep the pan covered until the feeding and preparation equipment is needed.

5. Hands should be washed thoroughly with soap and water before removing feeding and preparation equipment from a sterilizer or pan. The use of sterilized kitchen tongs for handling sterilized feeding and preparation equipment is recommended.

Follow eMaxHealth on YouTube, Twitter and Facebook.
Please, click to subscribe to our Youtube Channel to be notified about upcoming health and food tips.

6. To prevent recontamination, it is best to remove feeding and preparation equipment just before it is to be used. If equipment is removed from the sterilizer and not used immediately, it should be covered and stored in a clean place. Feeding bottles can be fully assembled to prevent the inside of the sterilized bottle and the inside and outside of the teat from becoming contaminated.

After sterilizing the bottles, the next step is to wash away any residual microparticles that remain. The authors amended the WHO recommendations with directions to:

• Prepare sterilized water by boiling the water in a non-plastic kettle/cooker (e.g. glass or stainless steel).

• Then, rinse the sterilized bottle(s) using room temperature sterilized water at least 3 times.

Preparing Infant Formula—now that the infant feeding bottles are ready for use, the next step of the process is to follow good infant formula prep technique.

• Prepare hot water ahead of time using a non-plastic kettle/cooker.

• Prepare infant formula in a non-plastic container using at least 70 degrees C water. Cool to room temperature and then transfer prepared formula into the previously sterilized and rinsed high-quality plastic infant feeding bottle.

Standard Precautions—Avoid these mistakes that could cause microparticle release

• Do not reheat prepared formula in plastic containers and avoid microwave ovens.

• Do not vigorously shake the formula in the bottle at any time.

• Do not use sonication to clean plastic infant feeding bottles.

“…The last thing we want is to unduly alarm parents, particularly when we don’t have sufficient information on the potential consequences of microplastics on infant health,” said Professor John Boland, a co-author of the study.

“We are calling on policy makers, however, to reassess the current guidelines for formula preparation when using plastic infant feeding bottles. Crucially, we have found that it is possible to mitigate the risk of ingesting microplastics by changing practices around sterilization and formula preparation.”

What To Expect When You Are Expecting With COVID-19

The authors state that future research will continue toward investigating specific mechanisms of micro and nano-plastic release during food preparation with an eye toward developing technologies that will prevent plastic degrading, as well as discovering effective filtration technologies that will remove micro and nano-plastics from the environment.

For more about protecting the health of your infants, here is an informative article titled “Bad News for Pregnancies with COVID-19 Infection, Reports New Study” and what the risks involved are with the coronavirus while pregnant.

Timothy Boyer has a Ph.D. in Molecular and Cellular Biology from the University of Arizona. For 20+ years he has been employed as a freelance health and science writer. Today, with an eye on the latest news, Timothy continues writing about science with a focus on what you need to know for healthier living. For continual updates about health, you can also follow Timothy on Twitter at TimBoyerWrites.

Image Source: Courtesy of Dirk (Beeki®) Schumacher from Pixabay


High levels of microplastics released from infant feeding bottles during formula prep” Trinity College Dublin News 19 Oct. 2020.

Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation” Li, D., Shi, Y., Yang, L. et al. Nature Food 19 Oct. 2020.