Final answer:
The presence of microorganisms in food is considered a biological hazard as they can cause foodborne illnesses.
Step-by-step explanation:
The presence of microorganisms (bacteria, viruses, parasites and fungi) in food is considered a biological hazard. These microorganisms can cause foodborne illnesses when consumed. Some common examples include norovirus, Salmonella, Clostridium perfringens, and Campylobacter.