Published: 28/06/19 08:50 Categories: Microbiology

Are you aware of the identification mechanisms of our TBX chromogenic agar?   

TBX Chromogenic Agar (Tryptone Bile X-Glucuronide) is based on Tryptone Bile Salts Agar medium, which is normally used to detect and enumerate Escherichia coli in foods. In addition to this base, TBX chromogenic agar adds a chromogenic agent, x-ß-D-glucuronide, which makes it possible to detect the presence of the enzyme glucuronidase, highly specific for E. coli.   

The color from the chromophore released by the agar makes the target colonies easier to identify. To release this color, the bacteria must absorb the chromogenic agent x-ß-D glucuronide and the intracellular glucuronidase enzyme activity breaks the bond between the chromophore and the glucuronide

The released chromophore is thus accumulated inside the cells, causing the colonies of Escherichia coli to present a distinctive blue-greenish color.    

This formulation is contemplated in the ISO 16649 standard, which describes a horizontal method for the enumeration of E. coli beta-glucuronidase positive in products intended for human consumption or animal feeding

Advantages of using TBX chromogenic agar


  • Results in 24 to 48 hours  
  • Easy interpretation and reading of results  
  • High specificity based on specific enzymatic reactions  
  • Improvement in efficiency and laboratory time  
  • Formulation according to ISO 16649 standard
  • Microbiological test according to ISO 11133 


Would you like to benefit from all the advantages our TBX Chromogenic Agar has to offer?  


Find it in the format you need: 






TBX Chromogenic Agar (Tryptone Bile X-Glucuronide)

500 g

ISO 16649


TBX Agar Chromogenic

10 x 100 ml

ISO 16649


TBX Agar Chromogenic

10 x 200 ml

ISO 16649


TBX Agar Chromogenic

20 plates (90 mm)

ISO 16649


If you need additional information about these products or those needed to complete the procedure for the 

detection and enumeration of E. coli in accordance with the ISO 16649 standard, please do not hesitate 

to contact us.