In food safety policy, a "zero tolerance" standard generally means that if a potentially dangerous substance (whether microbiological, chemical, or other) is present in or on a product, that product will be considered adulterated and unfit for human consumption. In the meat and poultry inspection program, "zero tolerance" usually refers to USDA's rule that permits no visible signs of faecal contamination (feces) on meat and poultry carcasses.