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XLT4 Agar Base
XLT4 Agar is used for the isolation of non-typhi Salmonella spp. This medium is predominantly effective when used with samples where overgrowth of contaminating flora is anticipated. In order to inhibit the growth of non-Salmonella organisms, the medium is supplemented with Tergitol 4. Meat Peptone and Yeast Extract provide nitrogenous sources for the optimal growth of Salmonella spp. Xylose, Lactose, and Sucrose are the main fermentable carbohydrates. Upon their utilization, the pH indicator Phenol Red shifts from red to yellow. Thiosulfate and Ferric Ammonium Citrate detect hydrogen sulfide production in alkaline conditions by the formation of a black precipitate. Sodium Carbonate stabilizes the pH and Sodium Chloride maintains the osmotic equilibrium. There is a choice of 3 sizes - 500g, 2kg, and 10kg.
PREPARATION: Mix 59 grams of the medium and 4.6mL of Tergitol 4 in one liter of purified water until evenly dispersed. Heat with frequent agitation and boil for one minute. DO NOT AUTOCLAVE. AVOID OVERHEATING OF MEDIUM.