Product number: NCM2021

Hektoen Enteric Agar is used for the isolation and differentiation of enteric pathogens.

Hektoen Enteric Agar was developed in 1967 by King and Metzger. Compared to other enteric differentiating media commonly used, Hektoen Enteric Agar increased the isolation rate of Salmonella spp. and Shigella spp. This was accomplished by increasing the carbohydrate and peptone content of the medium in order to counteract the inhibitory effects of bile salts and indicators. King and Metzger formulated a medium that slightly inhibited growth of Salmonella and Shigella, while inhibiting Gram-positive microorganisms.

Enzymatic Digest of Animal Tissue provides nitrogen, carbon, and amino acids required for organism growth. Yeast Extract is a vitamin source. Bile Salts Mixture and Acid Fuchsin inhibit Gram-positive organisms. Lactose, Sucrose, and Salicin are fermentable carbohydrates. Sodium Chloride maintains the osmotic balance of the medium. Ferric Ammonium Citrate, a source of iron, allows the detection of hydrogen sulfide (H2S) produced from Sodium Thiosulfate. H2S-positive colonies have black centers. Bromothymol Blue is added as the pH indicator. Agar is the solidifying agent.


Formula Liter
Enzymatic Digest of Animal Tissue 16.5 g/L
Yeast Extract 3.0 g/L
Bile Salts Mixture 4.5 g/L
Lactose 12.0 g/L
Sucrose 12.0 g/L
Salicin 2.0 g/L
Sodium Chloride 5.0 g/L
Sodium Thiosulfate 5.0 g/L
Ferric Ammonium Citrate 1.5 g/L
Bromthymol Blue 0.065 g/L
Acid Fuchsin 0.1 g/L
Agar 13.5 g/L

pH: 7.6 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.


  1. Suspend 75 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.

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Order Details

Product # Product Description
NCM2021A Hektoen Enteric (HE) Agar CE, 500 g
NCM2021B Hektoen Enteric (HE) Agar CE, 5 kg
NCM2021C Hektoen Enteric (HE) Agar CE, 10 kg
NCM2021D Hektoen Enteric (HE) Agar CE, 25 kg (European only size)
NCM2021E Hektoen Enteric (HE) Agar CE, 50 kg (US only size)

Reference Material

NCM2021 - Hektoen Enteric (HE) Agar CE, Safety Data Sheet [Danish] [Dutch] [English] [EU English] [Finnish] [French] [German] [Hungarian] [Italian] [Spanish, Mexico] [Swedish]

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