Microplastics in microwave heating and takeout containers
In a 2023 US study, food in polypropylene containers or polyethylene bags released more particles after 3 minutes in a microwave than when stored in the refrigerator or at room temperature. However, another study found none in polypropylene containers under any condition, so the results differ depending on the size measured.
Amounts found in studies
| Study | What was tested | Size range and method | Results |
|---|---|---|---|
| Hussain et al. (2023) | Polypropylene containers and polyethylene bags (for infant food) | — (confirmed in the abstract) | After 3 minutes in a microwave, 4.22 million micro- and 2.11 billion nano-sized particles per cm² of container. Bags (polyethylene) released more than containers. Microwave heating released more than refrigerated or room-temperature storage |
| Guo et al. (2024) | Plastic containers | — (confirmed in the abstract) | 23,702–490,330 particles per liter, 77–92% smaller than 0.005 mm. 534,109 when heated directly in a microwave |
| Jin et al. (2024) | Boiling water in takeout containers | Nile Red staining | Release was in the order polystyrene > polypropylene > PET > polylactic acid |
| Caponigro et al. (2025) | Containers at 100°C | Micro-Raman | 17 particles for PET, 30 for polystyrene. None found in polypropylene containers under any condition |
| Du et al. (2020) | Takeout containers in China | — (confirmed in the abstract) | 3–29 particles per container. 30% were the same material as the container, and the rest appear to have fallen from the air. No change when soaked in boiling water |
Results can differ by orders of magnitude depending on the smallest particle size counted and whether particles are counted or weighed. Numbers from different studies cannot be compared directly (→ Why numbers differ).
Good to know
- The concentration used in the cell experiments in Hussain 2023 (1,000 μg per mL) is far higher than the amount people take in.
- One study also reports that shaking during delivery (physical impact) contributes a great deal (Son et al. 2024).
- No study directly comparing with glass or ceramic dishes was found.
What you can do at home (shown in research)
- In the studies, microwave heating of plastic containers released the most particles (Hussain 2023, Guo 2024). One option is to transfer food to a glass or ceramic dish before heating, but no experiment comparing the two was found.
Data from Japan
No study measuring Japanese containers was found. To check whether a container can be used in a microwave, look at the “heat-resistant temperature” under the Household Goods Quality Labeling Act and the product’s labeling (→ Regulations and systems).
Types of plastic found
Related explainers
Sources
- Hussain KA et al. Environ Sci Technol 2023;57:9782 (PMID 37343248)
- Guo et al. J Hazard Mater 2024;462:132798 (PMID 37856957)
- Jin T et al. J Hazard Mater 2024;475:134866 (PMID 38870856)
- Caponigro V et al. Food Chem 2025;464:141716 (PMID 39447258)
- Du F et al. J Hazard Mater 2020;399:122969 (PMID 32526446)
- Son et al. 2024 (PMID 39536343)
Last checked 2026-10-01. “Confirmed in the abstract” means we report only what the paper's abstract says. This page is a translation of our Japanese page; if they differ, the Japanese page is the reference.