Chemical analyses have identified plastic particles in selected commercial salts. Sea salt is not the only salt type in the literature: retail studies also include rock, black, table, and pink salts. Reported counts depend strongly on the extraction size threshold, particle selection, and definition of plastic. These findings do not supply a universal salt concentration or establish a health effect from consuming the tested products.12
What this page covers
This page uses direct studies of edible commercial salts. Research on salt-marsh sediment, hypersaline ecosystems, or salt solutions used to extract particles from soil does not measure a retail salt ingredient and is not substituted for food results. A salt’s source environment can inform hypotheses about contamination, but product occurrence still requires examination of the salt itself.
The selected studies differ in how finely they could extract and identify material. One intentionally used a coarse filter because finer filters clogged with salt-associated insoluble material. Another investigated smaller particles with microscopy and infrared spectroscopy. These are different observation windows, not competing measurements of the same salt sample.12
What the studies found
Scroll horizontally for methods and measurement limits.
| Study and endpoint | Reported result | Size and chemistry | Limit |
|---|---|---|---|
| Multi-country retail-salt study1 | 30 of 72 selected particles were confirmed plastic polymers | Coarse extraction above 149 µm; micro-Raman of selected particles | Pigments, amorphous carbon, and unidentified spectra were not all counted as confirmed plastic. |
| Selected salt types sold in Australia2 | 85.19 ± 63.04 study-classified particles/kg of salt | Observed particles 23.2 µm-3.9 mm; microscopy and selected ATR-FTIR | Author MP category includes rayon/cellulose acetate; not a strict synthetic-only population estimate. |
Why chemical identification changes the result
In the multi-country study, researchers dissolved salt, filtered insoluble particles, used a dense solution to separate material, and visually selected likely particles. Micro-Raman then tested the chemical composition of every selected object. Some objects were polypropylene or polyethylene, while others were pigments, carbon, or unresolved material. The confirmed-plastic subset was therefore smaller than the visually suspected subset.1
A lake-salt sample could not be analyzed because insoluble material blocked the filter. Excluding that sample is different from recording a nondetect. Likewise, failure to identify a spectrum does not prove that the object was plastic or that it was harmless. The paper reports those categories separately, and this page retains that distinction.1
The original paper also required a published correction because the plastic-polymer and pigment panels in a figure were inverted. The correction is a companion to the same dataset, not a new sampling study. This page uses the original results text for the numerical finding and records the correction so that readers do not confuse the figure panels.13
Evidence beyond sea salt
The Australia-market study sampled several terrestrial and marine salt types. It dissolved salt, used peroxide treatment, filtered the samples, and examined retained material by microscopy and fluorescence staining. Selected particles were then analyzed by ATR-FTIR. The measured average belongs to that selected set and is not a representative estimate for every salt sold nationally.2
The authors identified synthetic polymers including polyamide and polyurethane. Their classification also included rayon and cellulose acetate. Because natural and regenerated cellulose are not interchangeable with persistent synthetic plastics, this page labels the numerical result as study-classified particles and explains the material definition. The same category label in two papers need not represent identical particle chemistry.2
Some small particles did not yield usable infrared spectra, and the researchers excluded material below their effective spectroscopic size limit from quantification. The filter’s small pore size therefore should not be described as the validated particle-identification cutoff. SEM with elemental analysis supplied additional morphology and elemental information, but carbon and oxygen signals alone cannot distinguish a plastic fiber from natural material.2
Blank controls and measurement quality
The multi-country study used covered equipment, cleaned materials, filtered reagents, and procedural controls for water and density-separation solution. The Australia-market study processed procedural blanks alongside the salts and reported no particles in those controls. These precautions reduce laboratory contamination, but they do not eliminate other limitations such as visual selection, incomplete recovery, or ambiguous spectra.12
The second study pooled particles within salt type for spectroscopic selection. Its counts and chemical assignments should be read with that sampling procedure in mind. An average and standard deviation describe variability in the studied set; they do not define a maximum for future purchases or a concentration in an individual serving. No new serving-dose calculation is made here.2
Why salt studies should remain separate
A coarse-filter count cannot establish the absence of smaller particles. A broader small-particle count may also use another material definition or chemistry-selection rule. Combining these results into a category average would hide those differences. Neither study establishes whether a particular particle entered during salt formation, processing, handling, or packaging solely from its presence in a finished product.12
Regulatory status
The supplied EFSA statement is a dated scientific assessment that calls for improved methods and quality assurance. Its historical legislative description is not treated as a complete statement of current law. Neither that assessment nor the drinking-water measurement decision supplies a particle limit for this food category.45 A research concentration is not a product compliance determination. See source scope and versions.
What remains uncertain
The selected evidence does not establish a reliable contamination ranking for every salt source, complete coverage of nanoscale material, or a clinical outcome from salt-associated particles. The older paper’s health reassurance is not adopted as a measured finding because it did not test human outcomes. The defensible conclusion is that confirmed polymers occur in some tested salts and that precise counts require explicit size, material, and analytical context.12
References
- The presence of microplastics in commercial salts from different countriesResearch article
- Consuming microplastics? Investigation of commercial salts as a source of microplastics (MPs) in dietResearch article
- Corrigendum: The presence of microplastics in commercial salts from different countriesResearch correction
- Presence of microplastics and nanoplastics in food, with particular focus on seafoodScientific statement
- Commission Delegated Decision (EU) 2024/1441: methodology to measure microplastics in water intended for human consumptionLegal instrument