Any antimicrobial claim is only as strong as the test report that supports it. In practice, it is the efficacy test that defines whether a product can be communicated as antibacterial, antifungal or antiviral, whether it passes the scrutiny of a demanding customer and whether it withstands regulatory questioning.
In this article, you will see how an efficacy test works, which standards are commonly used for each type of material, how to read a test report with a critical eye and how to plan the validation of your product.
Why the efficacy test is decisive
For procurement, the test report is a supplier qualification criterion. For R&D, it is the evidence that the formulation works. For marketing and sales, it is what authorizes the claim. And for regulatory affairs, it is the basis of any discussion with authorities and customers. Without an adequate test, the claim loses its footing.
How an antimicrobial efficacy test works
Although each standard has its own details, the general logic is similar.
Basic test steps
A known quantity of microorganisms is placed in contact with the treated material and with an untreated reference material. After a defined contact time, under controlled temperature and humidity conditions, the surviving microorganisms are counted and compared.
How to interpret logarithmic reduction
Results are usually expressed as log reduction or as a percentage. A 2 log reduction equals 99% and a 3 log reduction equals 99.9%. The minimum value accepted for a claim depends on the standard, the type of product and the market. For this reason, the number alone must be read together with the method used.
Most commonly used standards by material type
The table below brings together common market references. Standards undergo periodic revisions, so always confirm the current version and its suitability for your product with the laboratory and with regulatory affairs.
[INSERT TABLE OF STANDARDS BY MATERIAL TYPE]
This table is a starting point. The final choice of standard must consider the type of microorganism, how the product is used and the requirements of the destination market.
Antibacterial, antifungal and antiviral claims require different tests
Each claim must be proven by a specific test: the antibacterial report supports the antibacterial claim, and the antiviral claim requires its own test. To understand these differences before defining the scope of validation, read the article on antibacterial, antiviral and antimicrobial technology.
How to read an efficacy report: a checklist for R&D and procurement
Before accepting a report as evidence, check:
- Standard and version used: is the method recognized and suited to the type of material?
- Laboratory: is it independent and accredited, such as ISO/IEC 17025, by a recognized body? In Brazil, accreditation is granted by Cgcre, part of Inmetro.
- Tested sample: is the tested material the same as the final product, with the same formulation and thickness?
- Microorganisms tested: which strains were used and whether they match the type of claim.
- Contact time and conditions: are they compatible with the standard and with real use?
- Untreated control: was a reference material used for comparison?
- Result: is it expressed as log reduction or percentage, and does it meet the standard’s criterion?
- Date and traceability: is the report recent and does it clearly identify the product and the lot?
Durability tests: efficacy holds up throughout use
An excellent initial result may not hold up after washing, abrasion or aging. In textiles, the test is usually repeated after wash cycles. In plastics and coatings, it is worth evaluating performance after repeated cleaning, wear and exposure. This data supports the claim throughout the product’s service life, from the moment it leaves the factory.
Efficacy, safety and regulatory registration are different stages
Proving efficacy takes place in a stage separate from regulatory approval. Depending on the product and the market, additional registrations, notifications or safety assessments may be required, especially for food-contact materials, healthcare products and export. To understand how this type of international validation works, read the article on EPA and FDA certifications for antimicrobials.
How to plan the validation of your product
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- Define the desired claim: antibacterial, antifungal, antiviral or combined.
- Map the destination markets: each country and each customer may have its own requirements.
- Choose the appropriate standards: according to the material and the claim.
- Test the final product: with the real formulation and production process.
- Include durability tests: washing, abrasion or aging, depending on use.
- Document and maintain traceability: reports, lots and versions of the standards.
- Align the communication with the results: the claim must reflect exactly what was proven.
This planning connects to the process described in the article on how the development of technology solutions works.
Frequently asked questions
Does a single report apply to all my products?
No. The report applies to the material, the formulation and the conditions tested. Relevant changes in resin, thickness, fabric or dosage may require new tests.
Can I use the raw material supplier’s report?
It is a good starting point, but efficacy in the final product depends on the formulation and the process. Ideally, test the final material.
How long is a report valid?
It depends on customer and market requirements, and on changes to the product. Many companies revalidate periodically or whenever a relevant change occurs.
Which tests do I need to export?
It depends on the country and the type of product. The safest path is to map the destination market’s requirements before defining the test scope.
Next step
If your company already has an antimicrobial technology under evaluation or needs to validate a product for a specific customer or market, the best path is to define, with the technical team, the test scope and the standards best suited to your case.
