Viruses are not living organisms but bits of reproductive material that attack human cells and hijack them. An infected cell then starts making more viruses until it can’t make any more, breaking open and releasing the new viruses into the body to infect more cells.
The most important viruses that cause foodborne disease are:
Viruses don’t grow in food, and one particle is enough to make you sick.
Symptoms can be severe gastroenteritis or similar to the ‘flu’. Generally the illness only lasts one or two days. The exception is Hepatitis A which can be a severe illness and last for many weeks.