Pathogens are typically categorized by their biological type. While bacteria are the most common cause of reported outbreaks, viruses like Norovirus cause the highest total number of individual illnesses. Food safety - World Health Organization (WHO)

Foodborne microbial pathogens are microorganisms—including bacteria, viruses, and parasites—that cause illness when ingested through contaminated food or water. According to the World Health Organization (WHO) , nearly 1 in 10 people worldwide fall ill annually from contaminated food, resulting in approximately 420,000 deaths.