National Occupational Competency Testing Institute (NOCTI) Cosmetology Practice Exam

With what concentration should scissors be disinfected?

1. 50% alcohol

2. 70% alcohol

3. 90% alcohol

4. 30% alcohol

The correct answer is: 70% alcohol

Disinfecting scissors effectively requires the use of a concentration that ensures optimal antimicrobial activity. A concentration of 70% alcohol is recognized as the ideal formulation for disinfection due to its balanced ratio of alcohol and water, which allows for better penetration of the alcohol into the cell membranes of microorganisms. This concentration is particularly effective in targeting a broad spectrum of pathogens, including bacteria, viruses, and fungi. The presence of water in the 70% formulation helps to slow the evaporation of alcohol, thereby extending the contact time with the surface being disinfected. This increased contact time enhances the overall efficacy of the disinfection process compared to higher strengths of alcohol, which can evaporate too quickly to be effective. Lower concentrations, such as 50% or 30% alcohol, lack the potency needed for thorough disinfection, as they may not provide sufficient antimicrobial action. Conversely, while 90% alcohol has a high concentration, it may not be as effective because it evaporates rapidly, limiting its contact time with microbes. Therefore, the use of 70% alcohol strikes the right balance for disinfecting scissors in a professional setting.