Microplastics Testing For Retailers: Labs, Methods & Claims
The Wellness Quality Institute helps retailers choose labs, interpret results, and make honest microplastics claims. Start testing with confidence.
Read articleHow to Avoid Unsubstantiated Clean Label Plastic Claims
Don't let vague "plastic-free" claims put your brand at risk. The Wellness Quality Institute turns your lab data into defensible, verified claims.
Written by: Scott Steveson, Specialist
Key Takeaways for Plastic and Microplastic Claims
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Absolute claims like “plastic-free” or “microplastic-free” cannot be backed by today’s lab methods across all particle sizes and plastic types.
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Scope-locked phrasing that states only what your data shows sharply reduces regulatory and litigation risk.
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Brands need to audit existing lab data for method limits, polymer panels, blank controls, and chain of custody before making plastic-reduction claims.
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Independent third-party review, such as the Wellness Quality Institute’s Plastic-Free Pathway Verification, turns lab reports into defensible, publicly verifiable claims.
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Learn how the Wellness Quality Institute can help your brand replace unsubstantiated claims with language your data can support at wellnessqualityinstitute.com.
How Exact Claim Language Connects to Your Data
The table below shows how common claim language ties to regulatory risk and what your lab data can honestly support. Each claim type is judged against a single test: whether the evidence matches the exact scope of what the label says.
|
Claim Type |
Example Language |
Regulatory Risk |
What the Data Actually Supports |
|---|---|---|---|
|
Absolute absence |
“Plastic-free” / “Microplastic-free” |
High, because the FTC Green Guides require substantiation before use, and no method confirms total absence across all particle sizes and polymer types |
Nothing, because no validated analytical method currently reaches below 20 µm (Raman) or 50 µm (infrared), leaving the nanoplastic range and smaller microplastic fractions undetectable |
|
Unqualified reduction |
“Significantly reduced microplastics” |
Medium to high, because vague comparative claims need a defined baseline, tested scope, and documented method under the FTC Green Guides 16 CFR Part 260 |
A reduction relative to a prior tested lot, within the method’s detection range, for the specific polymer panel screened, not a universal reduction |
|
Scope-locked non-detect |
“No target polymers detected above [X] µm using [method] in [product/lot]” |
Low, because the claim is bounded by documented method limits, polymer panel, and production period and matches what the data shows |
Exactly what the reviewed dataset supports: a non-detect result within the tested particle-size range, for the reviewed polymer panel, in the sampled production period |
|
Verified pathway |
“WQI Plastic-Free Pathway Verified” (Standard Met products only) |
Low, because results are reviewed against published criteria and approved language is tied to a public registry ID that defines the exact scope |
That the company’s dataset was reviewed and accepted under the Wellness Quality Institute’s standard, showing progress toward plastic-free goals within the verified scope |
Step 1: Audit Your Existing Lab Data for Four Critical Inputs
The Wellness Quality Institute starts with the data you already have, not with new testing. Most premium water, beverage, and supplement brands have commissioned independent lab work at some point. The real issue is whether that data can support any claim.
The audit checks four inputs: the lab’s analytical method and its validated detection range, the polymer panel (the specific plastic types the method can identify, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), PVC, nylon (PA), polycarbonate (PC), and polymethyl methacrylate (PMMA)), the blank and contamination controls that show how the lab handled background plastic in its own equipment and environment, and the chain of custody that documents how samples were collected, handled, and delivered.
Each input must meet clear quality thresholds or the dataset cannot support a claim. Common problems include methods that were not validated for the specific product matrix, such as a method built for clean water used on a carbonated or protein-rich drink, where sugars, pigments, carbonation, fats, and proteins interfere with detection. A 2026 systematic review of 42 peer-reviewed beverage studies found that these complex matrices create major analytical interference. Incomplete blank data, where the lab did not fully document background contamination, is another frequent gap that makes a “none detected” result impossible to interpret.
Step 2: Tie Each Claim to Particle Size, Polymer Types, and Production Period
After completing the Step 1 audit and confirming that your data is sound, you need to map each planned claim to the precise parameters your data covers. Many brands discover a gap between what their label promises and what their lab report actually proves.
Three dimensions define the scope of any honest plastic claim. Particle-size range is the most critical. The California State Water Board’s two analytical methods, SWB-MP2-rev1 using Raman spectroscopy and SWB-MP1-rev1 using infrared spectroscopy, are validated for particles greater than 20 µm and greater than 50 µm respectively, both up to 5,000 µm. Everything below 20 µm, including all nanoplastics (smaller than 1 µm), sits outside what these validated methods can reliably measure. The polymer panel defines which plastic types were screened. The production period identifies which manufacturing lots the data covers.
The most common mistake at this stage is stretching one SKU’s result across an entire product line. The same 2026 systematic review states that microplastic claims in beverages must tie to a specific sample set, production run, and analytical protocol, not to a whole line. A single test on one SKU from one lot supports a claim only about that SKU and that lot.
Step 3: Swap Absolute Claims for Scope-Locked Phrasing
Scope-locked phrasing tells customers exactly what your data shows, without overreach. The shift moves you from absolute language that implies total absence to clear language that describes what was tested, how it was tested, and what the results were.
Approved scope-locked phrasing links the result to its method, particle-size range, polymer panel, and production period. Instead of “microplastic-free,” a brand with qualifying data might state that its dataset was reviewed and accepted under the Wellness Quality Institute’s Plastic-Free Pathway Verification standard, with the tested range and polymer panel listed in the public registry record.
Prohibited language includes any form of “plastic-free,” “microplastic-free,” “nanoplastic-free,” “zero plastic,” or “100% plastic-free” as a product claim. As the comparison table shows, these absolute claims are indefensible with current measurement limits. A 2026 PhD thesis at Wageningen University reaches the same conclusion and finds that routine analytical testing cannot support claims of complete absence. The FTC Green Guides also state that “free of” claims are misleading if the substance cannot be confirmed absent, which is the case for plastic and microplastic content today.
The rewrite process should cover every place the claim appears, including packaging, websites, press materials, retailer listings, and social media. A recommended four-step claims audit framework suggests inventorying all environmental claims, mapping each to its evidence, grading them by risk, and using cross-functional sign-off before publication.
Step 4: Submit Your Dataset for Independent Review
A lab report and a defensible market claim are not the same thing. Self-reported results, even strong ones, look like marketing to buyers, retailers, and regulators because the company interpreting the data has a direct interest in the outcome. Independent review changes that perception.
The Wellness Quality Institute’s review standard, WQI-CS-01, aligns with the California State Water Board’s drinking-water microplastics reference framework. It uses the same two analytical methods, SWB-MP1-rev1 for infrared spectroscopy above 50 µm and SWB-MP2-rev1 for Raman spectroscopy above 20 µm. California’s framework serves as a technical reference because it is the strictest credible public standard available, not because verification is limited to California. California did not create, approve, authorize, or endorse the Wellness Quality Institute or its standard.
The review covers laboratory qualification, analytical method, product matrix, sampling, tested particle-size range, target polymer panel, reporting limits, blank results, spike recoveries (where a known amount of a substance is added to confirm the method can detect it), replicates, chain of custody, data recency, product scope, and production or sampling period. The minimum polymer panel includes PE, PP, PET, PS, PVC, PA, PC, and PMMA. The Wellness Quality Institute does not perform laboratory testing. It reviews data from a qualified independent lab, and this separation between testing and review keeps the verification independent.
The outcome is binary: Standard Met or Standard Not Met. Standard Met requires that the dataset meets all technical and data-quality requirements and that no reportable target polymer particles are detected within the tested range and approved reporting limits. A non-detect result alone is not enough, because the reporting limits must also meet the Wellness Quality Institute’s requirements. Standard Not Met remains private, is never disclosed publicly, and is never described as a failed product.
Step 5: Use Your Public Registry ID in Market Claims
Every Standard Met product receives a public registry entry. This record lists the verified party, product scope, matrix, production or sampling period, tested particle-size range, lower method limit, polymer panel, reporting limits, testing lab and its accreditation, verification date, expiration date, registry ID, approved result statement, and current status.
The registry ID turns a marketing claim into a checkable fact. Buyers, retailers, journalists, and regulators can look up the ID and see exactly what was reviewed, under which conditions, and for which products. Every public verification claim must include or link to the registry ID. Logo use cannot stand alone as a product claim and must connect to the Verification Scope record.
Verification remains locked to the reviewed scope. You cannot extend a company-wide or product-line claim from a single dataset. The verification period lasts 24 months from the sampling date of the most recent accepted dataset. Continued claim use after that date requires re-verification with current data. Expired entries stay visible and are marked “Expired,” so the record stays honest over time. A single assessment fee covers review, the verification decision, and registry listing, while independent lab testing is arranged and billed separately.
Why Plastic-Reduction Claims Carry Extra Risk
Plastic-reduction and microplastic claims sit at the highest enforcement and litigation risk level within clean-label marketing. These claims make a concrete statement about what is physically in the product, and current measurement science cannot fully support absolute statements.
The core technical limit is the detection floor. As noted earlier, current validated methods reach only to 20 µm for Raman and 50 µm for infrared at their lower limits. This leaves the fraction between 1 and 20 µm unvalidated and the entire nanoplastic range beyond reliable measurement. A “none detected” result always reflects that floor. It means none found above that floor, for the screened polymers, in the tested lot, not none present at all.
An April 2026 class action filing against a major soup brand claimed that microwavable packaging releases harmful microplastics when heated, showing how microplastic content has become active litigation territory. Morgan Lewis’s May 2026 analysis notes that labels using terms such as “plastic free,” “BPA free,” “natural,” or “pure” are often challenged when plaintiffs allege exposure to microplastics or synthetic contaminants. Scope-locked language backed by independent review offers the only defensible path forward.
Frequently Asked Questions
How long does the Wellness Quality Institute Plastic-Free Pathway Verification take, and what does a brand need to submit?
Timeline depends on how complete your existing lab dataset is. A brand that already has full method documentation, blank and contamination control records, chain of custody, and polymer identification results can move through review faster than a brand that still needs new testing. Required documentation includes the lab’s analytical method and validated detection range, the full dataset with reporting limits, blank results, spike recoveries, replicates, chain of custody, product scope, and the production or sampling period covered. The Wellness Quality Institute does not perform lab testing. If you do not yet have a qualifying dataset, you work with a qualified independent lab first, then submit the results for review.
What happens if the dataset does not meet the standard?
A Standard Not Met outcome stays completely private. It carries no public claim, no logo rights, and no registry listing. It is not described as a failed product, because the issue often lies in the testing, such as an unsupported method, incomplete blank controls, reporting limits that do not meet the standard, or an incomplete polymer panel. The brand can submit corrected or additional information later. The review process is designed so participation does not create public downside risk.
What is the difference between Wellness Quality Institute verification and certification?
Verification describes what actually occurred, which is an independent review of a dataset against a defined standard. Certification suggests a guaranteed state, such as a product being definitively free of a substance. That type of guarantee is not scientifically possible for plastic or microplastic content, because no lab method can confirm complete absence across every particle size, polymer type, and production lot. The Wellness Quality Institute intentionally avoids “certified” or “certification” for this program. The approved mark is “WQI Plastic-Free Pathway Verified,” which signals that a company’s lab data has been independently reviewed and shows progress toward plastic-free standards, not that the product contains no plastic.
Does Wellness Quality Institute verification align with California’s microplastics framework, and does that mean California endorses it?
The Wellness Quality Institute’s review criteria align with the California State Water Board’s drinking-water microplastics reference framework, including its two analytical methods (SWB-MP1-rev1 for infrared and SWB-MP2-rev1 for Raman) and its regulatory definition of microplastics. California’s framework serves as a technical reference because it is the strictest credible public standard for this testing. As noted earlier, California has no involvement with the Wellness Quality Institute. The state’s framework is simply a technical benchmark. Verification is not a California approval, a government certification, or a health or safety certification, and it is available to US companies nationwide.
How often does a brand need to re-verify, and what triggers a scope change?
The verification period lasts 24 months from the sampling date of the most recent accepted dataset. Continued claim use after that date requires re-verification with current data. This reflects lot-to-lot variability, because a result describes the production it came from, not future production. A scope change occurs when you modify the reviewed product, SKU, matrix, production process, or analytical method. Verification applies only to the specific product, dataset, tested particle-size range, polymer panel, and production period that were reviewed. Company-wide or product-line claims based on a single dataset are prohibited.
Conclusion: Turning Real Data into Defensible Claims
Absolute clean-label claims such as “plastic-free” or “microplastic-free” cannot be substantiated, because no lab method detects every particle size or polymer type. The five-step process here, which includes auditing existing data, mapping claims to tested parameters, using scope-locked phrasing, submitting datasets for independent review, and publishing a registry ID, gives brands a repeatable path from real data to claims they can stand behind. Independent review against published criteria is what turns a lab report into a market claim that can withstand retailer checks, regulatory review, and litigation. The Wellness Quality Institute’s Plastic-Free Pathway Verification closes that gap for US brands that have invested in testing and now need a credible way to show their progress.
