Answer: C - Contamination by chemicals or other toxins is the final source of foodborne illnesses after bacteria, viruses, parasites, and mold. The U.S. Food and Drug Administration lists chemical contaminants, metals, natural toxins, and pesticides as the primary causes of non-pathogenic foodborne illnesses.
Natural toxins are generally a byproduct of food processing techniques, and do not include toxins associated with inherently poisonous foods, such as some species of mushrooms or fish. Allergies are immunological conditions that are triggered by allergens, but allergic reactions are not considered a foodborne illness.
