Which of the following is an example of a biological hazard?

The choice of pathogenic bacteria as an example of a biological hazard is rooted in the understanding of how food safety is defined and categorized. Biological hazards refer specifically to harmful microorganisms that can cause foodborne illness. This includes bacteria such as Salmonella, E. coli, and Listeria, all of which can multiply in food if not properly managed, leading to potential health risks for consumers.

In contrast, the other options consist of hazards that fall into different categories. Cleaning chemicals represent chemical hazards that can contaminate food if residues are not properly cleaned. Metal fragments are classified as physical hazards that could result from equipment wear or damage, posing the risk of injury or choking. Plastic shards similarly fall under physical hazards, where fragments from packaging may inadvertently enter food products. None of these other categories pose the same level of microbiological risk that pathogenic bacteria do, making the identification of pathogenic bacteria as a biological hazard particularly significant in food safety protocols and HACCP planning.