Final answer:
The four methods of sterilization include gas, dry heat, chemical, and steam. Each method aims to achieve complete removal or killing of microbes, with moist-heat sterilization via steam autoclaving being the most effective due to better penetration of cells.
Step-by-step explanation:
Part of the four methods of sterilization includes gas, dry heat, chemical, and steam. These methods are employed to achieve sterilization, which is the complete removal or killing of all vegetative cells, endospores, and viruses from the targeted item or environment.
Dry-heat sterilization, such as flaming a loop, exists within aseptic techniques and involves the direct application of high heat capable of incineration. On the other hand, moist-heat sterilization involves the use of steam under pressure in an autoclave, which is the most effective sterilization method because it penetrates cells more adeptly than dry heat.
Gas sterilization utilizing compounds like ethylene oxide can be used for materials that are heat-sensitive. Chemical sterilants are also effective in killing all microbes, viruses, and with appropriate exposure times, can also kill endospores.