Chromogenic Coliform Agar (CCA)

//Chromogenic Coliform Agar (CCA)

Chromogenic Coliform Agar (CCA)

SKU: KM0056 Category:

Chromogenic coliform agar (CCA) conforms to the ISO 9308-1 guidelines for the detection, enumeration and isolation of coliforms and more specifically Escherichia coli in water samples by the membrane-filtration technique.

The colonial differentiation is provided by the chromogenic substrates, Salmon-GAL and X-glucuronide.
Salmon-GAL is used for the detection of ß-D-galactosidase enzymatic activity.
X-glucuronide is used for the detection of ß-D-glucoronidase enzymatic activity.
β-D-galactosidase, expressed by all coliforms, cleaves the Salmon-GAL substrate and producing red/pink coloured colonies.
Unlike other coliforms, Escherichia coli cleaves both Salmon-GAL and X-glucuronide producing a violet/blue coloured colonies.
Tryptophan is used to increase detection reliability by improving the indole reaction.

The peptones, sodium pyruvate and sorbitol support bacterial growth and simple recovery of sub-lethal thermally injured coliforms.
Sodium di-hydrogen phosphate and di-sodium hydrogen phosphate phosphate buffer the medium and sodium chloride is used to achieve osmotic balance.
The selectivity is attained by the addition of Tergitol® 7 as it inhibits the growth of Gram-positive bacteria.

Additional Information


Shelf Life (days)

Storage Temp (°C)

Dehydrated Medium Appearance

Prepared Medium Appearance

Prepared Medium Colour

Dehydrated PH

Prepared PH

Product Description

Organisms Ref. No Result
Escherichia coli NCTC 12241 Growth, blue/violet colonies
Escherichia coli ATCC 8739 Growth, blue/violet colonies
Enterobacter aerogenes NCTC 10006 Growth, red/pink colonies
Citrobacter freundii ATCC 43864 Growth, red/pink colonies
Pseudomonas aeruginosa NCTC 12903 Growth, colourless colonies
Enterococcus faecalis NCTC 12697 Inhibited


Recommended incubation: Aerobically at 37°C ± 1°C for 18-24 hours.




Enzymatic digest of casein1
Yeast extract2
Sodium chloride5
Sodium dihydrogen phosphate x 2H2O2.2
Disodium hydrogen phosphate2.7
Sodium pyruvate1
IPTG (Isopropyl-ß-D-thiogalactopyranoside)0.1
X-ß-glucuronide CHX salt0.1


Enzymatic digest of casein 1.0
Yeast extract 2.0
Sodium chloride 5.0
Sodium dihydrogen phosphate x 2H2O 2.2
Disodium hydrogen phosphate 2.7
Sodium pyruvate 1.0
Sorbitol 1.0
Tryptophan 1.0
Tergitol®7 0.15
IPTG (Isopropyl-ß-D-thiogalactopyranoside) 0.1
Salmon-ß-D-galactoside 0.2
X-ß-glucuronide CHX salt 0.1
Agar 10.0
Total 26.5
*Adjusted/supplemented as required to meet performance requirements



Suspend 26.5g of the medium in one litre of deionised / purified water. Allow the medium to soak whilst mixing for 10 minutes.Sterilise by boiling for 100°C for 1 minute with frequent stirring to completely dissolve the medium.
Cool to 45-50°C and aseptically dispense into appropriate sterile containers.