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Microwaving baby food containers releases billions of nanoplastics

A groundbreaking study from the University of Nebraska-Lincoln has revealed that microwaving plastic baby food containers can result in the release of billions of tiny plastic particles, raising serious concerns about the health implications for infants and toddlers

The research team found that when microwaved, each square centimeter of these containers can discharge in some cases over 2 billion nanoplastics and 4 million microplastics.

Alarming discovery 

While the potential health risks of ingesting these tiny plastic particles are yet to be fully understood, the study made a startling revelation: up to 75 percent of cultured embryonic kidney cells perished after just two days of exposure to these particles. 

This finding underpins the 2022 report by the World Health Organization (WHO), which advises limiting exposure to micro- and nanoplastics.

Need for public awareness

Kazi Albab Hussain, the study’s lead author and a doctoral student in civil and environmental engineering at the University of Nebraska–Lincoln, emphasized the need for public awareness. 

“It is really important to know how many micro- and nanoplastics we are taking in,” said Hussain. “When we eat specific foods, we are generally informed or have an idea about their caloric content, sugar levels, other nutrients. I believe it’s equally important that we are aware of the number of plastic particles present in our food.”

According to Hussain, understanding the quantity of micro- and nanoplastics we consume could be key to grasping the potential harm they might cause. He notes that several studies, including their own, demonstrate a strong link between the toxicity of these particles and the degree of exposure.

Focus of the study

The idea for this research stemmed from Hussain’s personal experience as a new father in 2021. The lack of studies focused on the release of plastic particles from plastic containers and pouches, which are common in the baby food market, motivated him and his team to investigate.

Using polypropylene baby food containers and a reusable polyethylene pouch, both approved by the U.S. Food and Drug Administration, the team conducted a series of tests. They filled the containers with deionized water or 3% acetic acid to simulate dairy products and other relatively acidic food items, then microwaved them at full power for three minutes in a 1,000-watt microwave. 

The team subsequently analyzed the liquids for microplastics, particles at least 1/1,000th of a millimeter in diameter, and nanoplastics, particles even smaller.

What the researchers learned 

The results varied depending on several factors, such as the type of container and its contents, but one disturbing trend was clear. Infants and toddlers consuming microwaved water or dairy products appear to ingest the highest relative concentrations of plastics. 

Simulated experiments on refrigeration and room-temperature storage of food and drink over a six-month period also suggested that these practices could trigger the release of micro- and nanoplastics.

Even with his knowledge, Hussain acknowledges the challenge of avoiding plastics in childcare. “For my baby, I was unable to completely avoid the use of plastic,” he admits. “But I was able to avoid those (scenarios) which were causing more of the release of micro- and nanoplastics. People also deserve to know those, and they should choose wisely.”

Kidney cells may be especially vulnerable 

In collaboration with Svetlana Romanova from the University of Nebraska Medical Center, the team exposed cultured embryonic kidney cells to the released plastic particles. After 48 hours, a staggering 77% of the kidney cells exposed to the highest concentrations had died. This outcome was more severe than the results of previous studies on micro- and nanoplastic toxicity.

The researchers speculate that kidney cells might be more vulnerable to these particles than other cell types. Additionally, the fact that polypropylene containers and polyethylene pouches release about 1,000 times more nanoplastics than microplastics raises concerns about the ability of these tiny particles to infiltrate cells.

Safer materials are needed

The full implications of micro- and nano- plastic consumption require further exploration, but the findings underscore the urgent need for alternative solutions in baby food storage. 

Hussain called for a concerted effort to develop safer materials. “We need to find the polymers which release fewer (particles),” he said. 

“I am hopeful that a day will come when these products display labels that read ‘microplastics-free’ or ‘nanoplastics-free.'” This is a crucial goal to ensure the safety of our most vulnerable populations.

The research is published in the journal Environmental Science & Technology.


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