shelf life
limited shelf life, expiry date on the label
composition
agar, 12 g/L , bile salt mixture, 1 g/L , chromogenic mixture, 0.731 g/L , peptone, special, 10 g/L , sorbitol, 4 g/L
final pH
6.8±0.2 (25 °C)
Application
HiCrome MS.0157 Agar is a selective medium recommended for the simultaneous detection of Escherichia coli, Escherichia coli 0157:H7 and coliforms in water and food samples. Escherichia coli 0157:H7 gives colorless colonies because of non-fermentation of sorbitol and absence of β-glucuronidase activity, whereas other strains of Escherichia coli having β-glucuronidase activity and fermenting sorbitol appear as steel blue colored colonies. In absence of tellurite various non Escherichia coli 0157:H7 may have some colony color. Addition of tellurite makes medium much more specific and selective.
Preparation Note
Suspend 27.7 g in 1000 mL distilled water. Boil gently to dissolve the medium completely. DO NOT AUTOCLAVE. Cool to 50°C. Mix well and pour into sterile petri plates. This medium can be made more selective by adding aseptically 0.25 mL of sterile 1% Potassium tellurite solution (Cat. No. 17774) to 1 litre molten and cooled medium (45°C).
Legal Information
HiCrome is a trademark of HiMedia Laboratories Pvt. Ltd.