What is the minimum percentage of alcohol that should be present in an alcohol-based hand sanitizer?

The minimum percentage of alcohol that should be present in an alcohol-based hand sanitizer is 60%. This concentration is recommended by health organizations such as the Centers for Disease Control and Prevention (CDC) because it has been proven to effectively kill a wide range of germs, including bacteria and viruses.

Alcohol-based hand sanitizers work by denaturing proteins and disrupting cellular membranes of pathogens. A concentration of at least 60% alcohol is necessary to ensure that the sanitizer can effectively penetrate the cell walls of germs and exert its antimicrobial effects. Lower concentrations are less effective and may not kill pathogens effectively, making it crucial to use a sanitizer that meets or exceeds this threshold.

This is why the other choices, such as 50%, 70%, and 80%, do not meet the minimum recommendation; while 70% alcohol is effective, it is not the minimum requirement, which is what the question asks for. Therefore, the choice of 60% aligns with established guidelines for effective hand hygiene using alcohol-based sanitizers.