Which method of sterilization uses steam under pressure?

The method of sterilization that uses steam under pressure is autoclaving. Autoclaving is a highly effective sterilization technique widely used in medical and laboratory settings. It works by generating steam and then increasing the pressure inside the autoclave chamber. This combination of high temperature and pressure effectively kills bacteria, viruses, fungi, and spores, ensuring that the items being sterilized are completely free from all forms of microbial life.

The process typically involves heating water to produce steam, which is then trapped and pressured in the autoclave. The standard temperature for autoclaving is usually set at 121 degrees Celsius (250 degrees Fahrenheit), maintained for a specific duration to ensure sterilization. This method is favored for its reliability and effectiveness, particularly for heat-resistant instruments and materials.

Other methods mentioned, such as dry heat sterilization, use hot air instead of steam, making it less effective against certain microorganisms. Radiation sterilization relies on ionizing radiation to kill pathogens and is typically used for single-use medical devices. Chemical sterilization involves the use of chemical agents to achieve sterilization and is not reliant on steam or pressure. Therefore, the autoclave stands out as the method specifically designed for steam sterilization under pressure.