Description
General description
ReadyPlate™ 55 agar plates are stackable specially designed plates that helps increase the safety during handling, transport, incubation and comes in a lockable format. ReadyPlate™ 55 agar plates come with a diameter of 55 mm and the medium is filled perfectly on the top which allows easy handling (laying of the membrane) on the agar and prevents formation of air bubbles. Chromocult® Coliform Agar (CCA) is a selective and differential chromogenic culture medium used for the microbiological analysis of water samples. Within 24 hours this medium enables the simultaneous detection, differentiation and enumeration of E. coli and coliform bacteria in drinking water.
Application
Chromocult® Coliform Agar is used for the simultaneous detection of Escherichia coli and coliform bacteria in drinking water, disinfected pool water and finished water from treatment plants by membrane filtration method.
Analysis Note
The interaction of selected peptones, pyruvate, sorbitol and phosphate buffer promotes rapid colony growth, even for sub-lethally injured coliform bacteria. The growth of Gram-positive bacteria as well as certain Gram-negative bacteria is inhibited by the presence of Tergitol™ 7 which has no negative effect on the growth of coliform bacteria. Further, the combination of two chromogenic substrates permits the simultaneous detection of coliform bacteria and E. coli.
Coliform bacteria detection: The substrate Salmon-GAL is used for the detection of β-D-galactosidase activity, which is characteristic for coliform bacteria. This interaction results in a pink to red color of the coliform colonies.
E. coli detection: The substrate X-glucuronide is used for the detection of β-D-glucuronidase activity. E. coli cleaves both Salmon-GAL and X-glucuronide, so that positive colonies take on a dark-blue to violet color. These are easily distinguished from other coliform colonies, which have a pink to red color. Some E. coli (3-4%) are β-D-glucuronidase-negative and appear as pink to red colonies.
Accompanying flora appears as colorless colonies, except for some organisms, which possess β-D glucuronidase activity. These colonies appear light blue to turquoise in color.
Legal Information
CHROMOCULT is a registered trademark of Merck KGaA, Darmstadt, Germany
READYPLATE is a trademark of Merck KGaA, Darmstadt, Germany
TERGITOL is a trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow
