Bondurant SW, et al. - Researchers sought to determine the persistence of antibacterial activity of hand sanitizers by comparing one with a non-alcohol-based formulation using benzalkonium chloride (BK) (0.12%) vs one with an ethanol-based formulation (63%) (comparator product). They used a technique modification prescribed in American Society for Testing and Materials protocol E2752-10 to measure the persistence of antibacterial activity against Staphylococcus aureus at up to 4 hours after application. Outcomes revealed a noticeable reduction in colony-forming units with the application of the test product (BK) at each of the three time points tested (3.75-4.16-log₁₀ reductions), while the comparator produced less than 1-log₁₀ reduction over the same period. These results indicate that the BK formulation has significantly improved persistent antibacterial activity vs the comparator ethanol-based formulation.