Which illness symptom should staff be particularly watchful for?

The correct choice emphasizes the specific symptom of excessive trips to the bathroom because it can be indicative of foodborne illnesses, particularly gastrointestinal issues like diarrhea. This symptom is critical for food service staff to monitor because it can signal that a worker may be contagious and could potentially contaminate food or surfaces. Gastrointestinal symptoms are often associated with pathogens such as norovirus, E. coli, and Salmonella, which can spread rapidly in food establishments.

In the context of food safety, staff members experiencing excessive bathroom trips should be encouraged to report this symptom immediately and, depending on the situation, may need to stay home to prevent the spread of illness. This proactive approach helps maintain a safe environment for both employees and customers. The other symptoms mentioned—fever, headaches, and fatigue—while also significant and often associated with illness, do not as directly signify a risk of spreading foodborne pathogens in the same immediate way that gastrointestinal symptoms do. Therefore, monitoring for excessive trips to the bathroom is especially crucial in the food service industry.