EFSA Review Questions Extent of Microplastic Release from Food Contact Materials

Despite widespread concern, EFSA’s findings indicate that microplastic release from FCMs occurs predominantly through mechanical stress—such as abrasion or friction during regular use—and is not primarily driven by chemical diffusion processes. Notably, nanoplastics (<0.1 μm) remain under-researched, with virtually no reliable data available to assess their occurrence or risk.

Methodological pitfalls and misinterpretations

A central theme of the review is the methodological inconsistency across published studies. EFSA flagged frequent issues with test conditions, sample handling, and analytical reliability. Many studies were found to overestimate particle counts, often mistaking precipitated additives or oligomers for microplastics. For instance, testing involving hot water followed by cooling and room-temperature filtration has been shown to lead to false positives due to additive precipitation.

EFSA also highlighted the widespread use of non-representative test simulants, such as pure water, and the lack of validation for many analytical techniques. Only a few studies employed robust identification methods like Raman spectroscopy combined with solvent rinsing or procedural blanks.

Friction and fibre shedding: the primary release mechanisms

Mechanical processes were identified as the dominant mechanism of microplastic release. Frictional actions—such as opening bottle caps, sealing Ziploc® bags, or using plastic cutting boards—can cause small quantities of plastic particles to detach. Similarly, fibrous materials like tea bags were found to shed microplastics, especially under high-temperature conditions such as brewing.

However, EFSA emphasised that most reported particle concentrations were considerably lower than sensational figures published in early studies. For example, well-controlled tests of infant feeding bottles found fewer than 3,000 particles per litre under hot-use conditions, with most not derived from the bottle material itself.

Recycled plastics and future uncertainties

Only two studies examined mechanically recycled FCMs, yielding inconclusive results. While one found slightly fewer particles in recycled PET bottles compared to virgin PET, the differences were not statistically significant, and source water variability confounded interpretation.

In its conclusion, EFSA states that no reliable estimate of dietary exposure to MNPs from FCMs can currently be made, and calls for method validation, nanoparticle detection improvements, and testing under realistic use conditions, especially involving fatty foods and non-polar plastics.