Which of the following could be a source of biological hazards in food?

Pathogenic micro-organisms are indeed a significant source of biological hazards in food. These microorganisms, which include bacteria, viruses, and parasites, can contaminate food and cause foodborne illnesses. When food is improperly handled, stored, or cooked, these pathogens can multiply and lead to infections upon consumption. Understanding this risk is crucial for ensuring food safety, as it directly impacts public health.

The other options, though they may present hazards, do not fall under the category of biological hazards. Metal fragments and human hair are considered physical hazards, which can lead to injury but do not cause biological disease. Meanwhile, chemical detergents represent chemical hazards, which can result in toxicity if ingested but are not classified as biological in nature. Recognizing the differences between these types of hazards is essential for effective food safety management.