1. A. Pathogenic Streptococci – Gram stain a milk smear for the presence of long-chain streptococci together with neutrophils and do culture on BA to observe for hemolytic properties
2. B. Mycobacterium bovis – tuberculin test of cows demonstrates the infection; Guinea pig inoculation
3. C. Brucella abortus – subcutaneous guinea pig inoculation and perform autopsy 3-5 wks later; Cultures of milk for Brucella are frequently unsuccessful; Agglutination test (using animal serum) or skin test (brucellergin) is more reliable
4. D. Corynebacterium diphtheriae – Culture in Loeffler's Serum Agar Slants and Tinsdale medium
5. E. Coliform Group – presumptive evidence for the presence of coliform is gas formation within 24 hrs in Lactose broth with Durham's fermentation tubes
6. F. Typhoid/Parathyphoid (Salmonella Group) – use enrichment media first (tetrathionate broth) then inoculate in SSA and BSA and other selective media