<prompt> A microbiologist carries out milk ring test, which is positive. What is the most likely organism?SalmonellaBrucellaBordetellaBacillus anthracis  <response>: Milk Ring Test M is positive for Brucella. It is used for detection of infected animals in dairy farms, etc. A sample of whole milk is mixed with a drop of Brucella antigen and incubated at 70 degC for 40-50 min. If antibodies are present in the milk the bacilli are agglutinated and rise with the cream to form a blue ring at the top, leaving the milk unstained M positive. If antibodies are absent, the milk remains uniformly blue M negative Reference: Ananthanarayan and Paniker;s Textbook of Microbiology Tenth edition 