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Coliform ChromoSelect Agar

NutriSelect® Plus, suitable for microbiology

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Coliform Agar ChromoSelect



Quality Level



shelf life

limited shelf life, expiry date on the label


agar, 12 g/L
chromogenic mixture, 0.2 g/L
dipotassium hydrogen phosphate, 3 g/L
peptone, special, 3 g/L
potassium dihydrogen phosphate, 1.7 g/L
sodium chloride, 5 g/L
sodium lauryl sulfate, 0.1 g/L
sodium pyruvate, 1 g/L
tryptophan, 1 g/L


NutriSelect® Plus

final pH

6.8±0.2 (25 °C)


bioburden testing
food and beverages
water monitoring



selective and differential for Citrobacter spp.
selective and differential for Enterobacter spp.
selective and differential for Escherichia coli
selective and differential for Klebsiella spp.
selective and differential for Salmonella spp.
selective and differential for Shigella spp.
selective and differential for coliforms
selective and differential for enterobacteriaceae

Related Categories

General description

Coliform ChromoSelect Agar is a chromogenic mixture which contains two chromogenic substrates, Salmon-GAL and X-glucuronide. Coliforms produce an enzyme called β-D-galactosidase, which cleaves Salmon-GAL, resulting in the salmon-to-red coloration of coliform colonies. The enzyme β-D-glucuronidase produced by Escherichia coli cleaves X-glucuronide. Escherichia coli forms dark blue-to-violet colored colonies due to cleavage of both Salmon-GAL and X-glucuronide. The addition of tryptophan improves the indole reaction, thereby increasing detection reliability in combination with the two chromogens. To confirm Escherichia coli, add a drop of Kovac′s reagent (Catalog No. 60983) on the dark blue-to-violet colony. Formation of cherry-red color indicates the positive reaction.


Coliform ChromoSelect Agar is a selective chromogenic medium recommended for simultaneous detection of Escherichia coli and total coliforms in water and food samples.

Preparation Note

Suspend 27 g in 1 litre distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 121°C for 15 minutes. When a high number of gram-positive accompanying bacteria are expected, add 5 mg/l Novobiocin (Cat. No. 74675) before autoclaving of the medium.


We offer two media types: the superior granulated GranuCult® and the cost-efficient powdered NutriSelect® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

Legal Information

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany
NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany


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Hazard Statements

Hazard Classifications

Skin Sens. 1

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Customers Also Viewed

Slide 1 of 8

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Ronald M. Atlas, James W. Snyder
Handbook of Media for Clinical and Public Health Microbiology (2013)


Selective media enable faster results and visual confirmation for the detection, identification, and enumeration of microorganisms

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

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