Harlequin® Tryptone Bile Glucuronide Agar

Harlequin® Tryptone Bile Glucuronide Agar was developed for the detection and enumeration of E. coli in food products. E. coli are differentiated based on their production of the β-D-glucuronidase enzyme. Bile salts are included in the formula and act as a selective agent against Gram-positive organisms. This medium conforms to the performance requirements of ISO 11133:2014.


  1. Weigh 36.5 grams of powder and disperse in 1 liter of deionized water.
  2. Allow to soak for 10 minutes, swirl to mix.
  3. Autoclave for 15 minutes at 121°C.
  4. Cool to 47°C and mix well.
  5. Dispense into Petri dishes.
  6. Typical Formulation g/Liter
    Tryptone 20 g
    Bile Salts No. 3 1.5 g
    X-glucuronide 0.075 g
    Agar 15 g
    Grams per liter 36.5 g

    Final pH: 7.2 ± 0.2