Waste milk is an informal term referring to fluid milk that is not appropriate for use in food production for humans. There are a number of reasons the milk may not be used (such as its coming from a cow with mastitis i.e. high somatic cell count). Such milk is a potential risk for transmission of MAP to calves since the organism is shed into milk by infected cows or the milk is contaminated by manure containing the organism. Waste milk can be made safe if pasteurized on-farm. Alternatively, milk replacer (commercially prepared powdered milk) can be fed to calves prior to weaning with little or no risk of infecting the calf with MAP.