Microplastics in shrimp, crab and nori
For shrimp and other crustaceans, pooled studies give 0.1–8.6 particles per g. In a U.S. survey of protein foods, breaded fried shrimp had the most. For nori, there is a survey of commercial products in China, in which larger particles increased the more the nori was processed.
Amounts found in studies
| Study | What was tested | Size range and method | Results |
|---|---|---|---|
| Danopoulos et al. (2020) | Crustaceans (meta-analysis) | Varies by study | 0.1–8.6 particles per g |
| Milne et al. (2024) | Commercial protein foods in the U.S. | Particles of 0.045 mm or larger counted under a microscope, some confirmed by Raman and FTIR | Breaded fried shrimp was the highest, averaging 370 particles per serving (large variation) |
| Li Q et al. (2020) | 24 brands of commercial nori in China | — (confirmed in the abstract) | 0.9–3.0 particles per g of dry weight. The more processed the nori, the more 1–5 mm particles and the larger the share of polypropylene and polyethylene (possibly introduced during processing) |
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
- 72% of the “microplastics” counted in Milne 2024 were fibers such as dyed cotton and cellulose, and only 18% could be identified as synthetic polymers (→ Meat and protein foods).
Data from Japan
We found no study that measured nori, shrimp or crab from Japan.
Types of plastic found
Sources
- Danopoulos E, et al. Environ Health Perspect 2020;128:126002 (PMID 33355482)
- Milne MH, et al. Environ Pollut 2024;343:123233 (PMID 38159628)
- Li Q, et al. J Hazard Mater 2020;388:122060 (PMID 31955027)
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.