This document discusses biological, chemical, and physical hazards in food. It defines hazards as agents that can cause illness or injury. Biological hazards include microorganisms like bacteria, viruses, parasites, and protozoa. Chemical hazards can be naturally occurring, intentionally added like food additives, or unintentionally added. Physical hazards refer to extraneous matter found in food like glass, wood, or metal that should not be there. The document provides examples of specific pathogens and toxins that pose hazards in different categories.