Question

Which of the following is not a physical method for controlling microorganisms?

• A. Radiation
• B. Filtration
• C. Disinfection
• D. Desiccation

Hint:

• Physical methods of microbial control use physical means:
  • Heat (autoclaving, dry heat)
  • Radiation (UV, gamma rays)
  • Filtration
  • Desiccation (drying)
  • Low temperature (refrigeration)
• Chemical methods use chemical agents (e.g., alcohols, chlorine).
• Disinfection is a \textit{process} aimed at reducing pathogens, which can be achieved using either physical or chemical methods. It is not a physical method per se.

Answer 1

The Correct Option is C

To determine which option is not a physical method for controlling microorganisms, we examine each option:

• Radiation: This is a physical method. It involves using electromagnetic waves, such as UV or gamma rays, to destroy microorganisms.
• Filtration: This is a physical method. It removes microorganisms by passing a fluid through a filter with pores small enough to prevent their passage.
• Disinfection: This is not a physical method. Disinfection generally involves chemical agents to eliminate microorganisms on surfaces.
• Desiccation: This is a physical method. It involves removing moisture to inhibit microbial growth and reproduction.

Based on the analysis, the correct answer is: Disinfection