Which of the following could be considered a biological hazard?

A biological hazard refers to a substance that poses a threat to human health because it originates from living organisms. In this case, Salmonella is a type of bacteria that can cause foodborne illness, particularly when present in undercooked chicken. Consumption of chicken contaminated with Salmonella can lead to severe gastrointestinal issues and other health problems. This makes it an exemplar of a biological hazard, as it directly relates to pathogens found in food that may cause disease.

The other options listed pertain to different categories of hazards. Pesticide residues relate to chemical hazards, which involve potentially harmful substances used in agricultural practices. Glass shards belong to physical hazards, as they are non-biological objects that can cause injury or harm. Cross-contamination, while linked to unsafe food handling practices, does not by itself represent a biological hazard; rather, it refers to the process by which pathogens are transferred from one substance or surface to another, potentially leading to biological hazards if contaminated foods are involved.