Final answer:
A food handler should be excluded from the establishment if they have symptoms of a foodborne illness, such as vomiting, diarrhea, fevers, and aches. Common sources of contamination include contaminated food and touching contaminated surfaces.
Step-by-step explanation:
A food handler should be excluded from the establishment if they have certain symptoms that can indicate a foodborne illness. These symptoms include vomiting, diarrhea, fevers, aches, and pains. The length of time between consuming contaminated food and the onset of symptoms is known as the incubation period, which can range from a few hours to several days or even longer.
Some common sources of contamination include contaminated food like leafy greens, fresh fruits, shellfish, or water, as well as touching contaminated surfaces. It is important to note that certain groups of people, such as pregnant women, young children, older adults, and those with weakened immune systems, are more likely to develop a foodborne illness.