Instituto Valenciano de Microbiología

Masía El Romeral
Ctra. de Bétera a San Antonio Km. 0.3
46117 Bétera (Valencia)
Phone. 96 169 17 02
Fax 96 169 16 37
CIF B-96337217


ASTM E1883-02 (2015) - Standard Test Method for Assessment of an Antibacterial Handwash Product by Multiple Basin Wash Technique

Test Accredited by ENAC (National Accreditation Entity)

Test with the Certificate of Good Laboratory Practices (GLPs).


This test is used for the in vivo evaluation of the performance of antibacterial handwashing products intended to reduce the microflora of the skin after repeated use, covering the determination of the effectiveness of an antibacterial handwashing to reduce the level of aerobic bacterial flora in the hands, being able to evaluate the combined activity against the transient and the resident microbial flora. The count of a first wash is considered to correspond to the transient microflora and the count of one of the last wash of hands, probably more significant, corresponds to a resident population, more stable.

For this, the hands of a group of fifteen adult subjects and who have refrained from using any product containing antimicrobial agents for at least two weeks before the test (providing them with a personal grooming kit, without antimicrobial products, to be used exclusively during the test), are selected to perform a multiple handwash.

The assay includes a pre-test period, which consists of a period where the subjects wash their hands for at least two weeks before the first baseline reference sample, performing baseline bacterial counts of the first and/or fifth wash. The appropriate number of subjects whose baseline counts are closest to the median are selected to continue in the study. Once this pre-test period is over, the subjects stop using the kit provided and begin to use the test product, provided in the laboratory, with a register where they will record the use of the product at home. The subjects will wash with the test product during 11 consecutive days, three times a day, with intervals of one hour, being able to make up to five washes each time, under supervision in the laboratory, and they will continue using the test product at home for all handwashing, shower and bath. On the last day, twelfth, the subjects are washed with a soft formulation by sampling the hands for bacterial counts of the first and/or fifth wash. The handwashing procedure for a liquid test substance or other form must be specified by the client, specifying the amount of sample to be washed with and an appropriate washing time.

The data obtained will be used to evaluate the reduction of bacterial flora resulting from the use of the test antibacterial product, determining the bacterial counts per liter of the first and/or fifth wash of each sampling day and converting them into log10 to minimize the effect of the variability in the counts obtained from different subjects. The data of the baseline reference values ​​obtained from the first and fifth washings are averaged for each individual. These obtained reductions, calculated from the samples taken at the beginning and in the post-treatment after the fifth wash, will reflect the capacity of the test antimicrobial soaps to reduce the population of transient organisms in the hands.

The client must choose a contact time, a test concentration or indications on how much and how to add the product and the number of applications of the test substance that is to be incorporated in the test. The applicant for the test must record these requirements on the test form.