Which of the following statements correctly distinguishes between autoclaving and pasteurization in terms of their effectiveness for sterilization?

• A. Autoclaving and pasteurization are equally effective at killing bacterial endospores.
• B. Autoclaving achieves sterilization by using high-pressure steam, while pasteurization only reduces the number of viable microorganisms and does not sterilize.
• C. Pasteurization is more effective than autoclaving at sterilizing medical instruments.
• D. Both autoclaving and pasteurization achieve complete sterilization of all microorganisms.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definition of sterilization. Sterilization is the process of killing or removing all forms of microbial life, including bacterial endospores, which are highly resistant structures.
2. Step 2: Review the process of autoclaving. Autoclaving uses high-pressure saturated steam at temperatures typically around 121°C for a specific time (usually 15-20 minutes), which is effective at killing all microorganisms, including bacterial endospores, thus achieving sterilization.
3. Step 3: Review the process of pasteurization. Pasteurization involves heating a liquid (such as milk) to a temperature below boiling (e.g., 63°C for 30 minutes or 72°C for 15 seconds) to reduce the number of viable microorganisms, but it does not kill all microorganisms or bacterial endospores, so it does not achieve sterilization.
4. Step 4: Compare the effectiveness of autoclaving and pasteurization. Autoclaving achieves complete sterilization by killing all microorganisms and spores, while pasteurization only reduces microbial load to safe levels without sterilizing.
5. Step 5: Conclude which statement correctly distinguishes the two methods. The correct distinction is that autoclaving achieves sterilization using high-pressure steam, whereas pasteurization reduces viable microorganisms but does not sterilize.