How and why is the efficacy of biocidal products demonstrated?

When registering a biocidal product, proving its efficacy is a key requirement. Regardless of whether it is a surface or hand disinfectant, an insecticide, or a rodenticide, the declared purpose must be demonstrated. Efficacy is defined as the product’s ability to fulfill the claims of its intended use when applied according to the instructions for use. That is why I am presenting an overview of some tests used to demonstrate the efficacy of biocides and explaining why this is important.

To begin with, let us recall two key elements that define a product as a biocide:

• The product must contain a biocidal active substance (a substance whose action causes the biocidal effect of the product), and
• The purpose of the product must be the destruction, deterrence, neutralization, prevention of action, or other control of harmful organisms.

A biocide can most easily be recognized by the biocidal claim indicated on the label. HOWEVER – a biocidal claim, which communicates the product’s biocidal effect to the customer, must be demonstrated by standardized laboratory or other tests. Unsubstantiated claims are considered misleading.

Appropriate efficacy test results are a prerequisite for registration and market placement. In EU, this is a requirement prescribed by the applicable biocides legislation. The efficacy of a biocidal product is demonstrated in accordance with European or other international standards (CEN, ISO, OECD, etc.), which define test procedures for biocides according to their intended purpose, i.e. the type of biocide. A product is considered effective if it ensures an adequate level of harmful organism reduction (e.g., ≥ 5 log bacteria (99.999%)) or an appropriate mortality rate (e.g., > 90% of mosquitoes).

The most common standards for testing disinfectants (PT 1–5) include:

• EN 1276 – Testing bactericidal activity: checks the product’s ability to destroy bacteria; used for products in the food and other industries, households, and institutional environments.
• EN 1650 – Fungicidal activity: tests efficacy against fungi, molds, and yeasts for household, industrial, and professional products.
• EN 13697 – Bactericidal and fungicidal activity: simulates real conditions on hard surfaces; suitable for surface disinfectants.
• EN 14476 – Virucidal activity: used for products against viruses in healthcare settings; particularly important for products intended to prevent the spread of disease.

For other types of products, such as insecticides and rodenticides, field tests (simulation of real use conditions) are performed in addition to laboratory tests. If a standardized test cannot be applied due to the product’s form and purpose, other methods based on strong scientific evidence are acceptable.

Efficacy testing is carried out by accredited laboratories wherever possible, and the choice of test depends on the product’s intended purpose (type of biocide) as well as on its form and method of use. The guiance for the efficacy of biocidal products, which are regularly published and updated by the European Chemicals Agency, are also taken into account.

What is actually assessed by efficacy tests? They evaluate:

• how quickly and effectively the product destroys microorganisms or other harmful organisms,
• under which conditions (temperature, organic load, concentration),
• on which surfaces (e.g., glass, plastic, steel),
• at what dilution and contact time.

All these parameters are important and need to be examined to ensure that the product truly works as stated on the label. Based on the test results, the instructions for use are also defined – specifying the method of application that guarantees efficacy (e.g., “clean the surface before using the disinfectant” or “leave to act for 5 minutes”).

Be careful: Whenever you state biocidal claims on a product, they must be supported by appropriate testing.

If you need assistance in choosing the right test for your product or are looking for a laboratory to perform the required testing, write to me at tim.bencik@bens-consulting.eu.