This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Milk ring test is done for: 
Select and explain. 
A. Brucellosis, B. Bacteriodes, C. Tuberculosis, D. Salmonellosis
A: Brucellosis
Answer: A: Brucellosis 
Explanation: Ans. is 'a' i.e., BrucellosisDiagnosis of infect animal by Milk ring test - In this a sample of whole milk is mixed with a drop of stained brucella antigen. (A concentrated suspension of killed brucella abortus stained with hematoxylin) and incubated in water bath at 70degC for 40 to 50 minutes. 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. If the antibodies are absent no ring is formed and the milk remains uniformly blue.