Parameter | Original BSI-PAS-2424-2015 method | Applied modification | Rationale |
---|---|---|---|
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. |