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.
[1]: 279 In the United States meat and poultry inspection program, "zero tolerance" usually refers to the USDA rule that permits no visible signs of fecal contamination (feces) on meat and poultry carcasses.
[1]: 279 USDA requires that any time such fecal contamination is detected, it must be removed from the carcass.
[1]: 272 At issue is how this rule has been applied and enforced by USDA in meat and poultry plants.
[1]: 272 USDA early in 1997 clarified its zero tolerance rule for poultry; a year earlier it gave beef plants permission to use a new high-temperature vacuuming method to remove fecal contamination in lieu of cutting it off.