Chinese authorities are probing reports that a unit of China Modern Dairy sold milk cows that tested positive for tuberculosis, sending shares of the raw-milk producer to its lowest in more than a year. The reports alleged several of the 94 dairy cows sold by the subsidiary in an auction tested positive for bovine TB, while some tested positive to a brucellosis antibody serum test, Maanshan-based China Modern Dairy said in a statement to the Hong Kong Stock Exchange. Humans can contract TB by drinking unpasteurized raw milk from infected cows.