Which of the following is NOT a route through which microorganisms can spread from an infected animal?

Touch is not typically considered a direct route for microorganisms to spread from an infected animal to another host, especially when compared to the other options provided. Air allows for the transmission of airborne pathogens, while saliva can contain infectious agents that are easily passed between animals or from animals to humans. Feces can also harbor a variety of microorganisms that can lead to the spread of infection, especially if ingested or come into contact with an open wound.

Understanding how microorganisms spread is crucial for animal control officers to protect both animal and public health. Unlike direct fluid transmission through saliva or airborne dissemination, "touch" implies a more incidental contact that does not guarantee the transfer of pathogens, which is why it is the correct answer in this context.