Triple Sugar Iron Agar

Triple Sugar Iron Agar is used for the differentiation of microorganisms on the basis of dextrose, lactose, and sucrose fermentation and hydrogen sulfide production in a laboratory setting. Triple Sugar Iron Agar is not intended for use in the diagnosis of disease or other conditions in humans.

In 1911, Russell described the use of two sugars in a medium to differentiate Gram-negative organisms of intestinal origin. Lead or iron salts were added to Russell's medium to detect the presence of hydrogen sulfide. Kligler added lead acetate to Russell Double Sugar Agar, resulting in a medium capable of differentiating typhoid, paratyphoid, and dysentery. A modification of this medium was developed, Kligler Iron Agar, using Phenol Red as an indicator and iron salts to detect hydrogen sulfide production. In 1940, Sulkin and Willett described a triple sugar ferrous sulfate medium for use in identification of enteric organisms. Triple Sugar Iron Agar is essentially the formula originally described by Sulkin and Willett

Triple Sugar Iron Agar is recommended for differentiation of enteric, Gram-negative bacilli from dairy samples and food products.


Formula Liter
Enzymatic Digest of Casein 5 g
Enzymatic Digest of Animal Tissue 5 g
Yeast Enriched Peptone 10 g
Dextrose 1 g
Lactose 10 g
Sucrose 10 g
Ferric Ammonium Citrate 0.2 g
Sodium Chloride 5 g
Sodium Thiosulfate 0.3 g
Phenol Red 0.025 g
Agar 13.5 g

Final pH: 7.3 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 60 g of the medium in one liter of purified water.
  2. Heat with frequent agitation and boil for one minute to completely dissolve the medium.
  3. Dispense into tubes and autoclave at 121°C for 15 minutes.
  4. After autoclaving, allow medium to solidify in a slanted position.

Order Details

Product # Product Description
7162A Triple Sugar Iron Agar, 500 g
7162B Triple Sugar Iron Agar, 2 kg
7162T Triple Sugar Iron Agar, 5 kg