Culture media are sterilized by:
**Core Concept**
The underlying principle being tested is the method of **sterilization** used for culture media, which is crucial for preventing contamination and ensuring the growth of desired microorganisms. **Autoclaving** is a common method used in microbiology laboratories.
**Why the Correct Answer is Right**
Autoclaving involves using high-pressure steam to kill microorganisms, making it an effective method for sterilizing culture media. This process denatures proteins and disrupts cell membranes, ultimately leading to the death of microorganisms.
**Why Each Wrong Option is Incorrect**
**Option A:** Is not a standard method for sterilizing culture media.
**Option B:** May be used for disinfection but is not suitable for sterilizing culture media.
**Option D:** Is used for preserving specimens, not for sterilizing culture media.
**Clinical Pearl / High-Yield Fact**
Remember that **autoclaving** is the most commonly used method for sterilizing culture media due to its effectiveness in killing a wide range of microorganisms.
**Correct Answer:** D. Autoclaving.