Triple Sugar Iron

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Protocol
Recipe
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Recipe

Pancreatic digest of casein USP (see Note)	10.0 g
Peptic digest of animal tissue USP (see Note)	10.0 g
Glucose	1.0 g
Lactose	10.0 g
Sucrose	10.0 g
Ferrous sulfate or ferrous ammonium sulfate	0.2 g
NaCl	5.0 g
Sodium thiosulfate	0.3 g
Phenol red	0.024 g
Agar	13.0 g
Distilled water	1,000 mL

Note: The following combination of ingredients can substitute for the first two components listed: beef extract, 3.0 g; yeast extract, 3.0 g; and peptone, 20.0 g.

Combine ingredients, and adjust the pH to 7.3. Boil to dissolve the agar, and dispense into tubes. Sterilize by autoclaving at 121°C for 15 min. Cool in a slanted position to give a 2.5-cm butt and a 3.8-cm slant.

TSI agar is also available commercially.

Reference: Gephart, P., R.G. E. Murray, W.A. Wood, and N.R. Krieg. (1994) Methods for General and Molecular Bacteriology, ASM Press, Washington. DC.