Does Fresh-Smelling Laundry Mean It Is Truly Sanitised?
Fragrance, softness and stain removal are immediately noticeable. The antimicrobial efficacy of a laundry product, however, is invisible and needs to be demonstrated through controlled and reproducible testing.
This topic is explored in “The Invisible Power of Clean: Inside ASTM E2274”, an article by Matteo Calassanzio, Head of the Microbiology Department at Renolab, published in the latest issue of Tentamus Italia’s T-Magazine.
How the ASTM E2274 Method Works
ASTM E2274-24 is a test method used to assess the activity of laundry sanitising and disinfecting products under standardised washing conditions.
The study uses fabric carriers inoculated with selected microorganisms. Following treatment, the reduction in the microbial population is measured both on the fabric and in the wash water.
The method therefore evaluates product performance on textile fibres while considering the interaction between the main elements of a washing cycle:
- the product and its use concentration;
- water;
- the fabric carrier;
- temperature;
- treatment time;
- mechanical action;
- the presence of an organic soil load.
Reproducible Testing with the Launder-Ometer®
Renolab performs these studies using the Launder-Ometer®, an instrument equipped with stainless steel canisters rotating inside a thermostatically controlled bath.
The equipment makes it possible to control temperature, treatment time and mechanical action, providing repeatable experimental conditions. Several samples can be tested simultaneously to compare different formulations, dosages or conditions of use.
Biological residues can reduce or alter a product’s antimicrobial activity. To represent this variable, the protocol may include a standardised artificial organic soil load. This allows the product to be assessed under conditions that more closely reflect actual use while preserving the reproducibility of the study.
What Information Can Manufacturers Obtain?
A properly designed study can help manufacturers to:
- measure efficacy against the microorganisms selected for the test plan;
- assess different concentrations and treatment times;
- compare multiple formulations;
- support the definition of directions for use;
- generate data supporting efficacy claims;
- produce documentation for potential regulatory procedures.
ASTM E2274-24 was developed for conditions representative of traditional top-loading automatic washing machines. The experimental plan should therefore be defined according to the product’s intended use and the application scenario that needs to be represented.
Efficacy Claims and Regulatory Requirements
Products described as “sanitising” do not automatically fall within the scope of biocidal product legislation. Where the product’s claims, composition and intended use give it a biocidal function, its regulatory status should be assessed under Regulation (EU) No 528/2012.
Renolab supports manufacturers and regulatory teams in designing microbiological studies and efficacy testing for biocidal products, selecting microorganisms, experimental conditions and test parameters according to the product and the claims to be substantiated.