For selective isolation of Staphylococci causing food poisoning.

Dissolve 202.00 grams in 1000 ml distilled water, boil to dissolve the medium completely and sterilize by autoclaving at 15 lbs. pressure (121°C) for 15 min, cool it to 42-45 °C and continuously shake while distributing in petri plates. Ensure complete solidification and inoculate test sample aseptically. Mannitol fermentation test: Pick a colony from the medium on a cavity slide, add a drop of 0.04% bromothymol blue to the plate, and observe for the formation of a yellow color (positive reaction). Gelatinase test: Flood the plate with 5 ml of saturated ammonium sulfate solution and incubate at 35 ± 2°C for 10 minutes. Observe for a zone of clearing around the colonies (positive reaction).