Question

For sterilization, the culture media and glasswares must be generally autoclaved at:

• A. 121\(^\circ\)C and 19 psi
• B. 121\(^\circ\)C and 15 psi
• C. 112\(^\circ\)C and 15 psi
• D. 120\(^\circ\)C and 20 psi

Hint:

The combination of \textbf{121\(^\circ\)C} and \textbf{15 psi} is the universal standard for autoclaving in microbiology labs. Memorize this pair of values as they are fundamental to sterilization protocols.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Autoclaving is a sterilization method that uses high-pressure saturated steam. The goal is to eliminate all forms of microbial life, including highly resistant bacterial endospores, from media and equipment. This requires specific conditions of temperature, pressure, and time.
Step 2: Detailed Explanation:


The standard operating conditions for a laboratory autoclave are based on the temperature required to kill bacterial spores, which are the most heat-resistant life forms.

To achieve a temperature of 121\(^\circ\)C (250\(^\circ\)F) with steam, the pressure must be raised above normal atmospheric pressure.

The standard pressure used to reach 121\(^\circ\)C is approximately 15 psi (pounds per square inch) above atmospheric pressure.

These conditions (121\(^\circ\)C, 15 psi) are typically maintained for a minimum of 15-20 minutes to ensure complete sterilization, with the exact time depending on the volume and nature of the load.

Step 3: Final Answer:
The generally accepted standard conditions for autoclaving are 121\(^\circ\)C and 15 psi.