Which of the following activities would best prevent contamination in a microbiology laboratory?

• A. Handling cultures with bare hands
• B. Leaving culture plates uncovered
• C. Using tap water to rinse glassware
• D. Sterilizing equipment before use

Answer: (D)

Verified step by step guidance

1. Understand the concept of contamination in a microbiology laboratory, which refers to the unwanted introduction of microorganisms that can interfere with experimental results.
2. Evaluate each activity listed in the problem to determine its impact on contamination: handling cultures with bare hands can introduce microbes from the skin; leaving culture plates uncovered exposes them to airborne contaminants; using tap water to rinse glassware may leave residual microbes.
3. Recognize that sterilizing equipment before use is a critical step to eliminate all forms of microbial life, including spores, thus preventing contamination effectively.
4. Recall common sterilization methods such as autoclaving, dry heat, or chemical sterilants, which ensure that all instruments and media are free from contaminants before use.
5. Conclude that among the options, sterilizing equipment before use is the best practice to prevent contamination in a microbiology laboratory.