Final answer:
A foodborne virus can only reproduce in a person's intestines when contaminated food is consumed. It can infect a person's intestinal cells and replicate, leading to illness.
Step-by-step explanation:
A foodborne virus can only reproduce in a person's intestines. When infected people get stool or vomit on their hands and then handle food without washing their hands, the virus can contaminate the food. Once consumed, the virus particles can infect a person's intestinal cells and reproduce, causing illness.