Final answer:
Bob could potentially sue for disparate treatment if he were discriminated against due to a communicable disease; however, public health and safety concerns may legally justify the decision not to hire him for a food handling position.
Step-by-step explanation:
In relation to the refusal to hire Bob because he has a communicable disease for a position that involves cooking in a food truck, the theory of discrimination that could apply is disparate treatment. Disparate treatment occurs when an individual of a protected class is intentionally treated differently because of their membership in that class. However, public health concerns do legitimately allow for not hiring individuals with communicable diseases in jobs related to food handling, as that directly affects the health and safety of the public.
While not directly covered by the ADA, health and safety considerations can legally influence hiring decisions. To determine if Bob has a legitimate case, it would depend on the specific nature of his communicable disease and how it impacts his ability to perform the job safely and in compliance with public health regulations.