Which of the following is an example of biological contamination?

Biological contamination refers to the presence of harmful microorganisms, such as bacteria, viruses, parasites, and fungi, in food. Parasites are a specific type of biological contaminant that can cause foodborne illnesses when consumed. They can come from undercooked meat, contaminated water, and unwashed fruits or vegetables. Therefore, identifying parasites as a form of biological contamination is correct, as they are living organisms that can affect health.

The other options represent different types of contamination. Cleaners are chemical contaminants that can be harmful if ingested but do not fall under biological contamination. Foreign objects, like pieces of metal or plastic, are classified as physical contaminants. Pesticides, while harmful chemical substances that can contaminate food, are also considered chemical contaminants and do not fit the biological definition. This distinction is critical for understanding food safety practices and preventing foodborne illnesses.