Which of the following is a sign of dehydration related to foodborne illness?

Dry mouth and fatigue are indeed signs of dehydration, especially in the context of foodborne illnesses. When the body is dehydrated, it loses significant fluids, which can occur during episodes of vomiting, diarrhea, or fever that are often associated with foodborne pathogens. Dry mouth indicates that saliva production has decreased, a common response when the body is not adequately hydrated.

Fatigue is another critical indicator; dehydration can lead to lowered blood volume, which reduces the efficiency of the circulatory system and can make individuals feel weak and tired. Together, these symptoms suggest that the body is not only lacking water but is also struggling to maintain normal functioning due to fluid loss.

The other symptoms presented in the options do not indicate dehydration. An increased appetite typically suggests the body is seeking nutrition rather than indicating a lack of hydration. Increased energy levels would not correlate with dehydration, as the body's energy levels typically drop when it is deprived of fluids. Lastly, bloating and weight gain generally point towards fluid retention or digestive issues rather than dehydration, which reflects a different physiological condition.