Final answer:
The greatest threat to food safety among the given options is biological contaminants, which include pathogens like Norovirus and Salmonella that can cause foodborne illness. These biological agents are responsible for the vast majority of foodborne infections and can be controlled through proper food handling and safety practices. (option a)
Step-by-step explanation:
The question pertains to the three types of contaminants that can result in foodborne illness. Of the given options -- biological contaminants, chemical contaminants, physical contaminants, and cross-contamination -- the greatest threat to food safety can be attributed to biological contaminants.
This is because biological contaminants comprise various disease-causing germs like Norovirus, Salmonella, Clostridium perfringens, and Campylobacter, which are among the top pathogens causing illnesses from food consumed in the United States.
Biological contaminants include bacteria, viruses, and parasites that can cause numerous types of foodborne infections. Unlike chemical contaminants, which may not be eliminated by cooking or thermal processing, biological contaminants can often be mitigated through proper handling, cooking, and storing of food.
Government agencies and food safety practices aim to reduce the risk of foodborne diseases by addressing potential biological contaminations and encouraging behaviors like regular handwashing, avoiding cross-contamination, and maintaining safe temperatures during food storage.
Hence, the answer is option a