Which term describes microbes that cause illness in humans when consumed?

• A. Bacteria
• B. Yeasts
• C. Pathogens
• D. Spores

Answer: (C)

Illness-causing microorganisms are called pathogens. A pathogen is any microbe—whether a bacterium, virus, fungus, or parasite—that can invade the body and cause disease when ingested or inhaled. In food safety, we focus on pathogens to prevent foodborne illness, since they’re the agents responsible for sickness.

Bacteria and yeasts are broad categories of microbes; some are harmless or beneficial in certain foods, but not all cause disease, so they aren’t the specific label for illness-causing agents. Spores are a dormant form that some microbes can take to survive adverse conditions; they’re not themselves the illness-causing type, though they can contribute to persistence and later illness if they germinate in food. The term that best identifies those microbes that actively cause illness is pathogens.