September 8, 2023 – Results from recent laboratory experiments show that microwaving water- and milk-based beverages in common baby food containers releases amounts of microplastics and nanoplastics that may very well be potentially toxic over time.
The experiments weren't conducted on humans. Instead, human cells within the laboratory were exposed to the tiny plastic particles released during microwaving. Results were published earlier this summer within the magazine Environmental Science and Technology.
Researchers on the University of Nebraska-Lincoln conducted experiments with three varieties of common baby food packaging: two different baby food containers manufactured from polypropylene and a reusable baby food bag manufactured from polyethylene. The container types are FDA-approved, the authors said.
One set of containers was stuffed with water and one other set of containers was stuffed with an acidic liquid to mimic the properties of common baby foods and drinks comparable to fruits, vegetables or dairy products.
The filled containers were heated in a 1,000-watt microwave at full power for 3 minutes. The researchers then analyzed the liquids to find out whether or not they contained micro- or nanoplastic particles.
Microplastic particles are those which might be at the least 1/1000th of a millimeter, and nanoplastic particles are smaller than this size.
The researchers concluded that the absorption of the tiny plastic particles occurs most strongly when infants drink products containing microwaved water or when toddlers eat microwaved dairy products.
The study's writer, Kazi Albab Hussain, a doctoral student in civil and environmental engineering on the University of Nebraska–Lincoln, recently became a father, which was the inspiration for the research.
“I could not completely avoid using plastic for my baby,” Hussain said in a opinion“But I was able to avoid those (scenarios) that led to a larger release of micro- and nanoplastics. People also have a right to know about this and they should choose wisely.”
The researchers conducted a further laboratory experiment by which human embryonic kidney cells were exposed to the microplastic and nanoplastic particles detected after heating the infant food containers within the microwave.
They exposed the kidney cells to a much larger amount of particles than can be released in a single microwave and drink session. The amount of particles utilized in the experiment was what the researchers estimated can be the concentration of particles that accumulate over the course of many days or from multiple sources.
In laboratory experiments, roughly 75% of the kidney cells died inside two to 3 days, indicating potentially high toxicity.
“When we eat certain foods, we're generally informed or have an idea about their calorie content, their sugar content, [and] other nutrients. I consider it's equally essential that we're aware of the quantity of plastic particles in our food,” said Hussain. “Just as we understand the impact of calories and nutrients on our health, knowing the extent of plastic particle intake is crucial to understanding the potential harm they may cause. Many studies, including ours, show that the toxicity of micro- and nanoplastics is strongly related to the extent of exposure.”