This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Microbiology (Sterilization and Bacterial Genetics), Subject name: Microbiology
Most effective method of sterilization by heat is 
Select and explain. 
A. Hot air, B. Boiling, C. Steam, D. Steam under pressure
D: Steam under pressure
Answer: D: Steam under pressure 
Explanation: Most effective method of sterilization by heat is by using moist heat (steam) above atmospheric pressure Autoclave is a classical example. Principle of autoclave- when water boils under pressure, instead of boiling at 100 degrees, it boils at a higher temperature. Hence the steam generated is at higher temperature.