Which of the following is a method by which heat can be used to control microbial growth?

• A. Refrigeration
• B. Ultraviolet irradiation
• C. Autoclaving
• D. Filtration

Answer: (C)

Verified step by step guidance

1. Understand that heat control methods use elevated temperatures to kill or inhibit microbial growth by denaturing proteins and disrupting cell membranes.
2. Identify the options that involve heat: Refrigeration uses low temperatures, so it does not apply; Ultraviolet irradiation uses light energy, not heat; Filtration physically removes microbes without heat.
3. Recognize that autoclaving uses steam under pressure to achieve high temperatures (usually 121°C) that effectively sterilize materials by killing all forms of microbial life, including spores.
4. Recall that autoclaving is a standard heat-based sterilization method widely used in microbiology labs and medical settings.
5. Conclude that among the given options, autoclaving is the correct method that uses heat to control microbial growth.