Appearance (Colour)
Light yellow
Appearance (Form)
Free flowing, homogeneous powder
Solubility
36.57 gm/liter
Solubility before autoclaving (Clarity)
Clear to slightly opalescent
Gel strength (1.5% gel)
Firm, comparable with 1.5% agar gel
pH (25°C)
7.2 ± 0.2
Prepared Medium Appearance after autoclaving (Clarity)
Clear to very slightly opalescent
Prepared Medium Appearance after autoclaving (Colour)
Light yellow
Cultural Response
Inoculate and incubate at 37°C for 18-24 hours
Organism
Escherichia coli
ATCC 25922
Inoculum (cfu) 10-100
Growth : Good
Recovery Rate : >=50.0%
Colony colour : Blue- green
Organism
Staphylococcus aureus
ATCC 25923
Inoculum
10³
Growth : Inhibited
Organism
Salmonella enteritidis
ATCC 13076
Inoculum (cfu) 10-100
Growth : Good
Recovery Rate : >=50.0%
Colony colour : colourless
Applications
Recommended chromogenic medium, used for the detection and enumeration of Escherichia coli and coliforms from food samples.
Principle
Casein enzyme hydrolysate provides the nitrogenous sources for the growth. Bile salts inhibits the growth of gram-positive organisms. X-glucuronide is the chromogenic substrate which is activated upon by the enzyme glucuronidase, resulting in blue-green colonies.
Composition
Ingredients
gms/lt.
Tryptone
20..
Bile Salts mixture
1.50
X-Glucuronide
0.075
Agar
15.00
Directions
1. Add 36.57 gm powder to 1.0 liter of distilled/purified water and mix thoroughly.
2. Gently heat and bring to boiling.
3. Autoclave at 15 psi pressure at 121°C for 15 minutes.
