Get Plastic Out26 million specks. 230 confirmed plastic
230 per litre
confirmed polypropylene particles the tubs shed at the 1st use; 340 at the 50th
A lab microwaved water in new plastic tubs and counted about 26 million specks per litre. Nearly all of them dissolved in alcohol, which plastic does not. We read the re-test: what washed away, what stayed, and the $0 swap for leftovers.
What they found
In a 2022 study, a lab microwaved water in new polypropylene food tubs and checked it with the standard laser test for plastics (Raman). It found about 26 million particles per litre. The odd part: they looked like polyethylene, a different plastic. Testing whether additive specks fool this test, the team rinsed the filters with ethanol, which dissolves such specks, not plastic, and counted again.
Every polyethylene lookalike washed away. An infrared test (FTIR, which identifies a substance by the light it absorbs) pointed to slip additives such as stearic acid: ingredients added to plastic, not plastic itself. What stayed matched the tubs' polypropylene: 230 particles per litre, about 100,000 times fewer. The additive specks kept coming: still above 18 million per litre at the 10th and 50th uses. Another team saw the same trap in baby bottles: filtering the water hot (70 °C) instead of after cooling took particle counts of up to 15 million per litre down to at most 2,800 plastic particles per litre, in one bottle. None were the bottles' own material; most were likely lab background.
Evidence: Emerging
Why it matters
Still, the tubs shed their own plastic. Filled with 500 mL of water, microwaved 5 minutes, lidded and shaken, they released a few hundred confirmed polypropylene particles per litre at each use checked: 230 at the 1st, 390 at the 10th, 340 at the 50th. It didn't fade with use; clean-water blanks had none. EFSA, Europe's food safety agency, lists the 230 in a table of reliable, conclusive studies.
The swap
Heat food in a glass or ceramic dish
Before microwaving, tip leftovers from the plastic tub onto a microwave-safe glass or ceramic plate or bowl you already own, and heat them as thoroughly as you normally would. No need to throw your tubs out: keep using them for cold storage. If you do heat in plastic, use containers marked microwave-safe and stay within the label's limits. Replace any that are warped or cracked.
Cost: Free (uses dishes you already have) · Swap rating: Likely
What we don't know yet
One lab's tub study used water, not food, and gave no brand, tub count or microwave power; its chart reads a bit lower than its text. Heat and shaking weren't separated, nor was glass tested. Filter-patch counts were scaled up; specks under about 1 micrometre weren't reliably counted. EFSA says release is mainly from friction and wear; intake from food contact materials can't yet be estimated.
Sources
- Li D et al. (2022). Alcohol Pretreatment to Eliminate the Interference of Micro Additive Particles in the Identification of Microplastics Using Raman Spectroscopy. Environmental Science & Technology 56(17):12158-12168. https://doi.org/10.1021/acs.est.2c01551
- Gerhard MN et al. (2022). Can the presence of additives result in false positive errors for microplastics in infant feeding bottles? Food Additives & Contaminants: Part A 39(1):185-197. https://doi.org/10.1080/19440049.2021.1989498
- Pallavera M et al. (2024). Evidence of Sub-Micrometric Plastic Release When Heating Food Containers Based on Light Scattering Measurements. Particle & Particle Systems Characterization 41(12):2400029. https://doi.org/10.1002/ppsc.202400029
- EFSA (European Food Safety Authority) et al. (2025). Literature review on micro- and nanoplastic release from food contact materials during their use. EFSA Supporting Publications 22(10):EN-9733. https://doi.org/10.2903/sp.efsa.2025.EN-9733