Final answer:
Walter should use sterilization for cleaning tools because it is the highest level of infection control, ensuring the complete destruction of all microbes, as requested by their manager, Carlos.
Step-by-step explanation:
Since Carlos has requested the highest level of infection control which would destroy EVERYTHING, the appropriate recommendaction for Walter would be sterilization. This process involves complete removal or killing of all vegetative cells, endospores, and viruses, ensuring that the tools are free from any potentially infectious agents. Sterilization can be accomplished physically through high heat and pressure or chemically with sterilants. In the context of infection control, disinfection and sanitization are insufficient as they do not ensure the complete destruction of all forms of microbial life; instead, they aim to reduce the microbial load to safe levels or remove enough microbes to achieve levels deemed safe for public health, respectively.