Product Description
TBX Chromogenic agar (Tryptone Bile X-Glucoronide) is a modification of Tryptone Bile Salts Agar medium, used for the detection and enumeration of E. coli in food samples, with the addition of a chromogenic agent, x-β-D-Glucuronide, to detect glucuronidase activity, highly specific for E. coli. The intracellular glucuronidase enzyme breaks the bond between the
glucuronide and the chromophore, which builds up in the cells and turns E. coli colonies into a blue-green color.
PREPARATION
Mix 36.6 grams of the medium in one liter of purified water until evenly dispersed. Heat with repeated stirring and boil for one minute to dissolve completely. Distribute and autoclave at 121°C for 15 minutes. Cool to 45-50 ºC, mix well and dispense into plates.
QUALITY CONTROL SPECIFICATIONS
1. The powder is homogenous, free flowing and beige.
2. Visually the prepared medium is light to medium yellow, with trace to light haze.
3. Expected cultural response after 18-24 hours at 44 ºC.
| ORGANISM | RESULT | |
| Enterococcus faecalis ATCC 19433 | Inhibited | |
| Escherichia coli ATCC 25922 | Good Growth (>50%) – Blue colonies | |
| Pseudomonas aeruginosa ATCC 27853 | White to green-beige colonies | |
| Enterococcus faecalis ATCC 29212 | Inhibited | |
| Citrobacter freundii ATCC 43864 | White to green-beige colonies | |
| Escherichia coli ATCC 8739 | Good Growth (>50%) – Blue colonies | |
| Escherichia coli CECT 9153 | Good Growth (>50%) – Blue colonies |
STORAGE
Store the sealed bottle containing the dehydrated medium at 2 to 30°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original color.
