Biosecurity refers to policies and measures taken to protect this nation's food supply and agricultural resources from both accidental contamination and deliberate attacks of bioterrorism. Now viewed as an emerging threat, bioterrorism might include such acts as introducing pests intended to kill U.S. food crops; spreading a virulent disease among animal production facilities; and poisoning air, water, food, and blood supplies. The federal government is now increasing its efforts to improve biosecurity to lessen the vulnerabilities to bioterrorism threats.