Question

Which of the following statements is/are true for sterilization?

• A. Autoclaving at \(121^\circ C\) for \(20\) minutes destroys endospores
• B. Filtration through \(0.22\,\mu m\) membrane removes viruses from liquid
• C. Dry heat sterilization requires higher temperature and longer time than moist heat sterilization
• D. Gamma radiation sterilizes heat-sensitive medical equipment

Hint:

Moist heat sterilization is more efficient than dry heat sterilization because steam transfers heat more effectively and penetrates microorganisms better.

Answer 1

The Correct Option is A, C, D

Step 1: Goal of sterilization.
Sterilization wipes out every microbe, even tough endospores. We judge each method.

Step 2: Autoclave.
Moist heat at $121^\circ C$ for about $20$ minutes does kill endospores, so statement A is true.

Step 3: Filtration.
A $0.22\ \mu m$ filter holds back bacteria, but viruses are much smaller and slip through. So statement B is false.

Step 4: Dry heat and gamma rays.
Dry heat moves heat poorly, so it needs higher temperature and longer time than moist heat, making C true. Gamma radiation is the go to for heat sensitive items like syringes and gloves, so D is true.

Step 5: Answer.
\[ \boxed{A,\ C,\ D} \]