Which of the following is required for a chemical agent to be considered an effective disinfectant?

• A. It must rapidly kill or inactivate most vegetative microbes on surfaces.
• B. It must sterilize by destroying all forms of microbial life, including spores.
• C. It must only inhibit microbial growth without killing any organisms.
• D. It must be safe for ingestion by humans.

Answer: (A)

Verified step by step guidance

1. Understand the definition of a disinfectant: A disinfectant is a chemical agent used to reduce or eliminate harmful microorganisms on inanimate surfaces, but it does not necessarily sterilize.
2. Recognize the difference between disinfection and sterilization: Disinfection aims to kill or inactivate most vegetative (actively growing) microbes, while sterilization destroys all forms of microbial life, including resistant spores.
3. Evaluate the options based on the role of a disinfectant: It should rapidly kill or inactivate most vegetative microbes on surfaces to be effective, but it does not need to sterilize or be safe for ingestion.
4. Eliminate incorrect options: Since disinfectants do not sterilize, the option requiring destruction of all microbial life including spores is incorrect; also, disinfectants are not necessarily safe for ingestion, and merely inhibiting growth without killing is characteristic of a different type of agent (like a bacteriostatic agent).
5. Conclude that the key requirement for an effective disinfectant is its ability to rapidly kill or inactivate most vegetative microbes on surfaces.