In a microbiology laboratory, how often should the solution in disinfectant containers be changed to ensure effective microbial control?

• A. Once a week, regardless of use
• B. Every month during routine cleaning
• C. At least daily or whenever visibly contaminated
• D. Only when the container is empty

Answer: (C)

Verified step by step guidance

1. Understand the purpose of changing disinfectant solutions: it is to maintain the effectiveness of microbial control by ensuring the disinfectant is potent and uncontaminated.
2. Recognize that disinfectant solutions can lose their effectiveness over time due to dilution, contamination, or chemical degradation.
3. Consider that visible contamination (such as cloudiness, debris, or discoloration) indicates the solution is compromised and should be replaced immediately.
4. Note that many microbiology guidelines recommend changing disinfectant solutions at least daily to maintain consistent antimicrobial activity.
5. Conclude that the best practice is to change the disinfectant solution at least daily or whenever it becomes visibly contaminated, rather than on a fixed weekly or monthly schedule.