There’s a fine line for parents who are sterilizing baby bottles. Killing germs is essential, but hotter water can also release more microplastics.
Researchers at Ireland’s Trinity College have found the amount of tiny plastic debris grows substantially along with water temperature. Using 10 of the world’s most common infant-feeding bottles, they tested how the containers shed plastic during exposure to liquids of varying temperatures.
At 158 degrees, the bottles released up to 16.2 million polypropylene microplastics per quart of water used. At 203 degrees, the amount of plastic released more than tripled. The findings were published in the journal Nature Food.
The researchers said there are steps parents can take to minimize microplastic shedding. These include preparing the sterilization water in a glass or stainless-steel container and allowing the bottles to cool before use. The clean bottles should also be rinsed at least three times with room temperature, sterilized water.
Handling infant formula in a standardized way can also reduce the leaching of microplastics. Formula should be prepared in a nonplastic container using water that is at least 158 degrees. Transfer the formula to a high-quality feeding bottle only after it has cooled to room temperature.
There are also a few things to avoid: Do not reheat formula in plastic containers and never use a microwave for reheating. Never shake the formula after it is in the feeding bottle. Ultrasonic cleaners should not be used to clean baby bottles.
With some extra care, parents can help lower the risk of their baby ingesting dangerous particles too tiny to see.