Test for hemolytic activity. Mark bottom of a plate into 6-8 equal sections with felt marking pen, and label each section. Inoculate a premarked 4 cm sq area of trypticase soy-sheep blood agar plate by gently touching medium surface with 2 mm loopful of 24 h culture suspension. (Six or more cultures can be tested simultaneously on each plate.) Incubate plates 24 h at 35C. Examine plates for hemolytic activity. B. cereus cultures usually are strongly hemolytic and produce 2-4 mm zone of complete (β) hemolysis surrounding growth. Most B. thuringiensis and B. mycoides strains are also β-hemolytic. B. anthracis strains are usually nonhemolytic after 24 h incubation.