Cystine Tryptic Agar (CTA) Sugars-Arabinose, Lactose, Mannitol, Raffinose, Salicin, Sucrose, Trehalose, Xylose
Purpose: Detection of carbohydrate utilization in microorganisms. Carbohydrate utilization is detected by the incorporation of the pH indicator, phenol red, in the medium. When the carbohydrate is metabolized, the medium is acidified resulting in a color change from red to yellow. Inoculate and incubate 48h at 37C. Positive: yellow color. Negative: no change in color.