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

Physical hazards in food safety refer to foreign objects that can accidentally become part of the food, posing a risk to the consumer's safety. In this context, hair is a prime example of a physical hazard because it can accidentally fall into food during preparation and serve as a contaminant. Customers finding hair in food can not only cause health and safety concerns but also lead to complaints and reputational damage for food service establishments.

Residual chlorine and Salmonella are not categorized as physical hazards; residual chlorine relates to chemical hazards, as it involves chemical residues that could be harmful if ingested in significant quantities. Meanwhile, Salmonella is a biological hazard, as it is a type of bacteria that can cause foodborne illness, but it does not fit the definition of a physical object that could alter the integrity of the food. Lastly, Hepatitis A is another biological hazard, being a virus that can contaminate food and result in illness, but it, like Salmonella, does not represent a physical hazard.