Toxic substance, toxicity mechanism, toxic effect. Nature and complexity of foods. Food safety standards, for their ingredients and for contaminants. Legislation and methods used to assess the safety of food, ingredients and contaminants. Food safety, adverse reactions to foods or their ingredients. Tolerance levels for food operations: pesticide residues, drugs used in animal husbandry, unavoidable contaminants. Substances for which a level of tolerance cannot be considered (toxins in fish, molluscs, crustaceans, microbial agents, bovine spongiform encephalopathy). Phytosanitary products, voluntary and food additives, antimicrobial additives. Food storage methods. Interaction between food and xenobiotics. Food legislation and consumer protection in Italy and the European Community.