ASTM E1115-11 (2017). Standard Test Method for Evaluation of Surgical Hand Scrub Formulations.

Test accredited by ENAC (Spanish National Accreditation Entity).

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

This standard is specifically designed to measure the reduction of the microbial flora in the skin, both immediate and persistent (continuous antimicrobial effect), after single, repeated treatments or both. To do this, the hands of a group of adult subjects, between 18 and 24 (for each combination of test substance to be analyze), and who have refrained from using any product containing antimicrobial agents for at least a week before the test for which they will be provided with a personal hygiene kit, without antimicrobial products, for exclusive use during the test.

The test product is evaluated, previously performing a handwash, to determine a first estimate of the basal population of microorganisms by sampling them. This basic procedure is repeated on days 3 and 7, or 5 and 7, to obtain three estimates of the baseline population line. The measurement of the immediate activity is carried out following a single handrub and the persistent activity can be measured by collecting samples after 3 and/or 6 hours, wearing the glove, or other selected times after the immediate sampling. If you want to measure the accumulated activity, the subjects rub a total of twelve times with the test substance, twice on day 1 and three times a day on days 2, 3 and 4, and once on day 5. The samples are collected after the frictions of days 1 and 5. This mimics the typical use and allows to determine the reduction immediately after a single use and after repeated uses. Bacterial recovery is carried out after the washings with the reference control and with the test product, placing bags in the right and left hand of the subject and adding sampling solution with neutralizer to each bag, aseptically recovering a known volume of sample for proceed to plant.

The effectiveness of the test material is measured by comparing the number of initial bacteria and a subsequent count after twelve days of hand washing with an antibacterial product. The results obtained in plate counts (CFU/hand) are used to calculate the reduction of the bacterial flora resulting from the use of the antibacterial test product. These counts are averaged and the log10 of the reductions are determined in each recovery/wash interval. The reductions in bacterial populations calculated from the samples taken initially and post-treatment after the fifth wash reflect the ability of the test antimicrobial soaps to reduce the population of transient organisms in the hands, such a significant reduction will be evaluated with the Wilcoxon statistical method.

The surgical friction technique to be performed before bacterial sampling can be carried out with water or without water, depending on the test formulations. The customer should give these indications of use as well as the concentration and instructions on how to add the product. The applicant for the test must record these requirements on the test submission form.