Final answer:
A food handler who has been vomiting should be symptom-free for at least 24 hours before returning to work, as vomiting can be an indicator of a foodborne illness.
Step-by-step explanation:
If a food handler has been vomiting, they should not return to work until they are symptom-free for at least 24 hours. Vomiting can be a symptom of foodborne illness, which can result from consuming contaminated food. These illnesses can lead to severe dehydration and other health complications, hence the critical importance of preventing transmission in a food service environment.
Given that symptoms such as nausea, diarrhea, and vomiting typically last 24-48 hours, it is essential for the individual to rest and recover, and to ensure no further spread of potential illness through food they handle.