What method is most effective for killing microorganisms?

The most effective method for killing microorganisms is sterilization. This process involves using methods such as autoclaving, which uses steam under pressure to achieve temperatures that destroy all forms of microbial life, including bacterial spores. Sterilization is the only method that achieves a complete elimination of all viable microorganisms, making it essential in situations where the highest level of cleanliness is required, such as in surgical instruments or laboratory equipment.

Disinfection, while also effective at reducing the number of pathogens on surfaces, does not guarantee the total destruction of all microorganisms. Some resistant forms, such as bacterial spores, may survive disinfection methods, which is why sterilization is preferred in critical areas. Cleaning and sanitization further lessen microbial presence but do not provide the comprehensive eradication that sterilization does. Thus, in terms of effectiveness for killing all microorganisms, sterilization stands out as the superior choice.