Which decontamination method is the least effective in removing all organisms?

Cleaning is recognized as the least effective method in removing all organisms because it primarily involves the physical removal of dirt, debris, and organic material from surfaces. While it is an essential first step in infection control, cleaning alone does not eliminate all pathogens or microorganisms.

In contrast, sanitation entails reducing the number of microorganisms to a safe level, while disinfection kills or inactivates a significant number of pathogens on surfaces. Sterilization is the most thorough method, effectively destroying all forms of microbial life, including spores. Therefore, while cleaning is crucial for establishing a clean environment, it does not achieve the same level of pathogen reduction as the other methods listed, making it the least effective in removing all organisms.