Assessing the Release of Microplastics and Nanoplastics from Plastic Containers and Reusable Food Pouches: Implications for Human Health.
Level 5 - mechanism / opinion, no new human data
Bench laboratory experiment, exposure modeling, and in vitro cell assay without human participants
PubMed 37343248 · doi:10.1021/acs.est.3c01942
What was done
The authors quantified the release of microplastics and nanoplastics from polypropylene plastic containers and polyethylene reusable food pouches under different conditions (microwave heating, room-temperature storage, and refrigeration) using deionized water and 3% acetic acid as food simulants. Exposure modeling was performed to calculate estimated daily intake for infants and toddlers. An in vitro assay measured cell viability of human embryonic kidney cells (HEK293T) exposed to extracted particles at 1000 µg/mL for 48 and 72 hours.
What was found
Microwave heating caused the greatest particle release: some containers released up to 4.22 million microplastics and 2.11 billion nanoplastics per square centimeter within 3 minutes. Refrigeration and room-temperature storage for over six months also released millions to billions of particles. Polyethylene pouches released more particles than polypropylene containers. Modeled highest estimated daily intake was 20.3 ng/kg·day for infants consuming microwaved water and 22.1 ng/kg·day for toddlers consuming microwaved dairy products. In vitro testing showed extracted particles at 1000 µg/mL caused 76.70% and 77.18% cell death in HEK293T cells at 48 and 72 hours, respectively.
Why it matters
This study demonstrates that common food-contact plastics shed substantial quantities of micro- and nanoplastics under standard microwave heating and prolonged storage, providing quantitative exposure estimates for vulnerable early-life populations.
Limits
The investigation was strictly laboratory-based using food simulants rather than real food matrices. Cytotoxicity was demonstrated only in an in vitro cell line at a high concentration (1000 µg/mL), without testing in vivo uptake, tissue accumulation, or clinical endpoints.
Cited by
- supports Plastics release micro- and nanoplastics at high levels at extreme temperatures, such as when microwave heating food in plastic containers.