Microplastics and baby bottles: what do studies actually measure?
A study published in 2020 measured up to 16.2 million microplastic particles per liter released by polypropylene bottles during the preparation of infant formula. European health authorities nevertheless did not conclude that there was any proven risk, owing to insufficient data. The subject is therefore documented in terms of exposure, but not in terms of effects.
This gap between a striking measurement and a risk assessment that is still open deserves explanation. That is what this article does, with figures and sources to support it.
What the study published in Nature Food showed
High figures, obtained under specific conditions
The work was published on October 19, 2020, in the journal Nature Food. It focused on polypropylene bottles, the most widely used plastic for this type of container.
The researchers followed the internationally recommended preparation protocol: sterilizing the bottle, then preparing the formula with hot water.
The measured release reached up to 16.2 million particles per liter. Sterilization and exposure to high-temperature water significantly increased this release.
Based on these measurements, the authors estimated infants’ daily exposure in 48 regions worldwide. The values ranged from 14,600 to 4,550,000 particles per person per day.
What the study does not say
The authors were explicit on this point. They conclude that there is an urgent need to assess whether exposure at these levels poses a risk to infant health.
In other words, the study quantifies exposure. It does not demonstrate any health effect, nor does it claim to.
This distinction is essential. Confusing “particles are present” with “these particles are harmful” means skipping an entire step in scientific reasoning.
What is the status of the health authorities’ assessments?
EFSA has not concluded
The European Food Safety Authority says it has not completed a comprehensive risk assessment of microplastics and nanoplastics in food. It specifies that, at this stage, it cannot draw conclusions about any potential health effects.
A June 2016 statement had already identified significant uncertainties and the lack of standardized methods for detecting and quantifying these particles. Work published in August 2021 confirmed major knowledge gaps.
The European Parliament requested a scientific opinion. It is due by the end of 2027.
A literature review published by EFSA on October 21, 2025, provides an important nuance. It concludes that these particles do indeed migrate from packaging and utensils, but at levels significantly lower than those suggested by some earlier studies.
The absence of official monitoring
There is currently no European system for monitoring microplastics in food. This lack partly explains the scarcity of field data.
ISO 16094-2, published in 2025, defines microplastics as particles whose largest dimension is between 1 micrometer and 5 millimeters. The very existence of this recent definition indicates how much the field is still developing.
Nanoplastics are a separate issue. More difficult to detect and potentially more bioavailable, they are the subject of particularly scarce data.
Why the figures vary so much from one source to another
Estimates of general dietary exposure suggest 28 to 502 microplastics per person per day, depending on the country. The discrepancy with the millions of particles measured in bottles seems difficult to understand.
This is explained by the methods. General estimates concern various foods, with detection thresholds and particle sizes different from those used in the study on bottles.
There is also no standardized analysis procedure. Two laboratories studying the same sample may arrive at different orders of magnitude.
That is precisely what the authorities emphasize: the data are still too fragmentary to characterize actual exposure and relate it to toxicological thresholds.
Should you stop using plastic bottles?
No health authority recommends it at present. Polypropylene remains approved for food contact, and its use has not been called into question by regulations.
A glass bottle is an alternative that does not release plastic particles. In return, it carries a risk of breakage and is heavier, factors to weigh up depending on how you use it.
There is a real risk of overreacting. Giving up properly prepared infant formula or changing the dilution ratios exposes the child to nutritional dangers that have been well documented for a long time.
Preparing a bottle is still governed by precise rules, particularly regarding the water used. We have detailed them in which water to use for a bottle.
Actions that reduce particle release
The study’s measurements themselves point to the available actions, since heat is the determining factor.
Prepare the milk in a non-plastic container, then transfer it once the temperature has dropped. This is the action that most directly affects the identified mechanism.
Rinse the bottle with cooled water after sterilization rather than filling it immediately with very hot water.
Avoid shaking a plastic bottle vigorously when it is filled with very hot liquid. Mechanical agitation while hot promotes particle detachment.
Finally, replace bottles that are visibly scratched or cloudy. A degraded surface releases more particles than an intact one.
What this article says about material choices
The mechanism involved is not specific to feeding bottles. It concerns the aging of plastics exposed to heat, friction, and time.
This is a concrete argument in favor of durable equipment made from stable materials, bought once rather than replaced every year. This approach aligns with what we explain in our guide to materials and safety for foam mats.
The same applies to certifications. Identifying the actual requirements is explained in our guide to CE, REACH, EN 71, and OEKO-TEX certifications.
Knowing how to read a product specification sheet remains the most useful skill. The method is described in how to read a technical specification sheet.
This material requirement underpins our approach, presented on the About us page.
Sources
- Li D. et al., “Microplastic release from the degradation of polypropylene feeding bottles during infant formula preparation,” Nature Food, October 19, 2020.
- European Food Safety Authority (EFSA), thematic page “Microplastics and nanoplastics in food,” accessed in September 2026.
- EFSA, “Literature review on micro- and nanoplastic release from food contact materials during their use,” October 21, 2025.
- EFSA, statement on micro- and nanoplastics in food, June 23, 2016, and proceedings of Scientific Colloquium No. 25, August 31, 2021.
- Food Chain Monitoring Platform, “Microplastics in food,” February 5, 2026.
- ISO 16094-2 standard, 2025, definition of microplastics.
