Human beings consume protein-rich foods to supply their nutritional requirements, mainly of animal origin, such origin lying in meat from different species (cattle, sheep, caprines, birds, pigs, fish and seafood/shellfish), milk and eggs. With the exception of some products derived from fishing, these foods are obtained from financial exploitations in which the animals’ health must be guaranteed, thereby ensuring that food is harmless. In several countries the safety of such food has mainly been focused on avoiding the transmission of zoonotic diseases, less attention thus being paid to potentially present chemical residues, perhaps due to the course of the resulting disease. Whilst infectious processes are frequently of the acute type, toxicosis caused by contaminants in foods (more than acute) may be chronic, silent and often lacking a known aetiological agent.