Abstract: A device for detecting, in the early stages of infection, the presence of mastitis, as well as other impurities, in an individual cow or other milk producing animal, using a filter, preferably made of polyester and being disposable, which filters all milk being extracted from the cow, the filter being held in a container placed in the individual vacuum line of a milking machine being used to extract milk from the cow, the claws of the milking machine placed on the cow dropping from the cow upon the presence of mastitis, without contamination of the milk held in the bulk storage facility, while permitting healthy milk to pass through the filter without interruption of the milking process.