Which is a method of sterilization that employs moist heat?

Moist heat sterilization is a method that effectively kills microorganisms through the use of steam at high temperatures. Steam under pressure, often achieved through a device known as an autoclave, is the primary example of this method. The high-temperature steam penetrates microbial cells, leading to protein denaturation and cell death, making it a reliable method for sterilizing heat-resistant instruments and materials in a clinical setting. This method is preferred for many medical items, as it ensures a thorough sterilization process.

In this context, the other methods mentioned utilize different approaches. Dry heat sterilization relies on high temperatures without moisture, which is less effective for most microorganisms compared to moist heat. Chemical sterilization involves the use of specific chemicals to achieve sterilization, rather than heat. Radiation sterilization utilizes ionizing radiation to eliminate microorganisms, which is a different mechanism altogether. Thus, steam under pressure stands out as the appropriate choice for a method of sterilization that utilizes moist heat.