Table 2 Description of modifications applied to the original BSI-PAS-2424-2014 protocol

Dry abrasion test cycles

Three cycles of dry&wet abrasion, with intermittent inoculations and disinfectant application in between cycles.

Three dry abrasion cycles (with each cycle including one forward and one backward motion) were applied on a coated surface before the bacterial inoculation

While the original test was devised to test antimicrobial properties of disinfectants in both dry and wet abrasions, our test was conceived for surfaces exposed to dry hand-touch or dry cloth abrasions only. Thus the test was conducted by exposing the coating to all the dry abrasions at once and then inoculating with the test bacteria.

Resuspension of viable cells after the abrasion test for enumeration.

Immersion of the tested surface into 10 ml of the neutralizer solution.

5ml of neutralizer solution (as per Table 1) and scraping of PET covers and PVC substrate slides with sterile scrapers 20 s in two directions after the application of the neutralizer solution.

The same cells resuspension method was used for all tests due to established high recovery efficiency and to minimize technical variations.