Valencian Institute of Microbiology
(I V A M I)

ASTM E2274-16 under the specific conditions of the BPR: 2023 Guidance. Standard test Method for evaluation of laundry sanitizers and disinfectants. Bactericidal, Fungicidal, mycobactericidal and virucidal activity.

Test accredited by ENAC (Spanish National Accreditation Entity), including the standard mandatory microorganisms, and additional yeasts and/or fungi and viruses for PT2 and PT3 products, according to BPR Guidance.

The BPR Guidance states that the test described by the ASTM E2274-16 Standard can be used for the evaluation of PT2 and PT3 products. Biocides can be used to treat textiles and fabrics in hospitals, health care facilities, industry, institutions or private homes, when relevant micro-organisms in the textiles have to be reduced. Textile disinfection PT3 products are mainly used to disinfects cloths used for teat cleaning/disinfection of dairy cattle before milking.These products can be in the form of laundry products which combine detergent and biocide or can be specialized products in the form of laundry additives which are added to the wash cycle or as finishing products (e.g. fabric softeners) which are added in the last rinsing step or as pre-treatment.

The method described by the ASTM E2274 is designed to evaluate the disinfectants or sanitary products of laundries used in automatic washing processes using volumes of usual wash water, applied to demonstrate the reduction or complete death of a bacterial population in tissues and wash water after a single wash. This method is designed for tests with vegetative bacteria but can be adapted for tests with fungi or viruses. The method simulates the washing conditions, for which a set of tissues inoculated with the microorganisms is placed in a volume of the solution of the evaluated product, in the proportion indicated by the manufacturer, and shaken. After a period of contact time, the washing water, the neutralizing liquid, and the tissue used, are individually grown in a quantitative manner (cleaning efficiency), or qualitatively (disinfecting efficacy).

According to the BPR Guidance, textile disinfection products must be at least sufficiently effective against bacteria and yeasts. For the other groups of organisms (fungicidal, virucidal and mycobactericidal activity), the corresponding tests should only be provided when activity against them is claimed. For temperatures from 60ºC (40ºC for PT3), tests against E. faecium allow affirmations against bacteria, yeasts, fungi and mycobacteria Test microorganisms according to the BPR Guidance for PT2 and PT3 products are indicated in the following table:

According to the BPR Guidance, the interfering substance most appropriate for the in-use conditions should be used. For instance, blood for products used in the medical area and protein for products used in industry, institutional and domestic areas are recommended. For products used during pre-wash and main wash, tests should be done under dirty conditions. For products used during the last rinse, tests should be done under clean conditions.

The interfering substances indicated by the BPR Guidance for PT2 in medical area PT2 are 0.3 g/L bovine serum albumin (clean conditions) and 3 g/L bovine serum albumin + 3 mL/L erythrocytes (dirty conditions). For other uses, such as industry, institutions and domestic area, the recommended interfering substances are 0.3 g/L bovine serum albumin (clean conditions) and 3 g/L bovine serum albumin (dirty conditions). For PT3, clean conditions must be performed with 3 g/L bovine serum albumin and dirty conditions with 10 g/L bovine serum albumin+ 10g/L yeast extract.

In this assay, six pieces of tissue are used for each microorganism. Three pieces for the test product and 3 pieces for the controls. These inoculated pieces are inserted between the folds of a 15 g piece of cloth and maintained inside the closed exposure chamber under agitation for the time specified by the manufacturer. Once the exposure time has elapsed, the supports and the inoculated pieces of tissue are removed and introduced into a neutralization broth. The filtrate of the neutralization broth, the neutralization broth itself and dilutions prepared therefrom, are cultivated to detect the presence of the inoculated microorganisms, as well as their reduction, if any, expressed in log₁₀. Duplicate validations of the microorganism count controls are included in the test. The counting of the surviving microorganisms after the washing simulation process is carried out by means of quantitative counts in duplicate, with 5 dilutions in base 10.

To be considered effective against the different microorganisms, the product must demonstrate a logarithmic reduction of 4 in the number of viable bacteria, and mycobacteria, and a logarithmic reduction of 3 for yeasts and fungi and a logarithmic reduction of 3 for viruses.