Other Biological Hazards

Viruses are even smaller than bacteria. They consist of genetic material surrounded by a protein layer. Viruses cause disease when they multiply inside the body. They do not grow or multiply in food, as bacteria do. Therefore, food-borne viral diseases are usually caused by direct contamination from people, food contact surfaces, or contaminated water.

Parasites are organisms that can survive only by living on or inside another organism. They take their nourishment from the organism they are living in. Human parasites are usually very small, but they are larger than bacteria. Most foods that can carry parasites are used in the hot kitchen rather than the bakeshop, although raw fruits and milk can possibly be contaminated.