Data Sheet
Chromocult® Coliform Agar
Selective agar for the simultaneous detection of total coliforms
and E. coli in drinking water and processed food samples
• US-EPA approved as alternative
method for detection of total coliforms
and E.coli in Water
• EU approved as alternative method for
detection of E. coli and coliforms (in Spain)
• AOAC™ approved as alternative method
for detection of total coliforms and E. coli
in processed food
Cat. No. 1.10426.0500
(500 g)
The manufacturing process for food and water often
results in metabolic injury to the microorganisms and/
Application
or reduction of microbial members. Sub lethal microbial Water testing
injury is caused by chemical or heat treatment as well For water testing the agar medium base should be used
as storage under frozen, dried or chilled conditions. with the addition of antibiotics. In the US-EPA study
Traditional culture media used for the detection of the agar medium base was supplemented with 10 mg
coliforms/E. coli often contain ox bile or bile salts to of cefsulodin per liter. The European study in Spain was
inhibit Gram-positive bacteria. These strong inhibitors performed with the agar medium base supplemented
however may limit the growth of the targeted micro- with the E. coli/Coliform Selective Supplement.
organisms if they are already sub lethally damaged. Chromocult® Coliform Agar is usually inoculated by the
membraneilter method. Filter an appropriate volume
of sample (e.g., 100 ml for municipal drinking water,
Benefits 250 ml for bottled water, or 1 ml for surface water)
• Save time: Fast method for simultaneous detection using a membrane ilter. Place the ilter on Chromocult®
of coliforms and E. coli in water and processed food. Coliform Agar ensuring that no air is trapped under-
• Safe analytic results: Safe detection of injured neath. Incubate the inoculated dishes aerobically at
bacteria because of careful selected inhibitors. Less 35 – 37°C in an inverted position for 24 hours. After
danger of false negative results, EPA and AOAC™ incubation, examine the plates for the presence of
approved. typical colonies of E. coli and other coliforms.
• Easy: Clear detection of coliforms and E. coli even in
presence high amount of accompanying lora. Just NOTE: The type of membrane ilter affects the size and
add the recommend Supplement. coloration of colonies.
• Save money: Easy conirmation of E. coli. Just add
a drop of Indole reagent to a colony and the cherry
Food testing
colour shows you whether it is E. coli or not.
For processed food samples the agar medium base can
be used without the addition of antibiotic supplements
(as in the AOAC™ study). For fresh food samples with
Intended Use a higher microbial load, Chromocult® Coliform Agar
ES (Merck Millipore cat. no. 1.00850) is recommended.
Chromocult® Coliform Agar is a selective and differential Chromocult® Coliform Agar is usually inoculated by the
chromogenic culture medium intended for use in micro- pour plate method. Using a sterile pipette, transfer 1 ml
biology laboratories analyzing food and water. Within of the liquid test sample (or 1 ml from the appropriate
24 hours this medium enables the detection, differen- dilution) to a sterile Petri dish. Pour into each Petri dish
tiation and enumeration of E. coli and coliforms from approximately 15 ml of the Chromocult® Coliform Agar
drinking water and processed food matrices such as while the medium is still liqueied, but only after the
frankfurters, cooked chicken and non-fat dried milk. medium has been cooled to 45 – 50°C in a water bath.
A careful selection of inhibitors used in the selective Carefully swirl the plate until the inoculum is thoroughly
media is required to ensure the growth and recovery of mixed with the medium. Allow the mixture to solidify on
these damaged microorganisms. Chromocult® Coliform a cool horizontal surface. Incubate the inoculated dishes
Agar contains Natriumheptadecylsulfat as an inhibitor aerobically at 35 – 37°C in an inverted position (agar side
of Gram-positive bacteria which has no negative up) for 24 hours. After incubation, examine the plates
effect on the growth of the targeted coliforms/E. coli. for the presence of typical colonies of E. coli and other
Chromocult® Coliform Agar is therefore the ideal coliforms.
medium for the detection of coliforms/E. coli in drinking
water and processed foods. More detailed information about validation studies,
limitation or performance characteristics are described
in the Technical Information.
Quality control
Test strains Inoculum (CFU/plate) % Recovery rate Colony colour Salmon GAL XGlucuronide
E. coli ATCC 11775 10 – 100 > 70 dark blue to violet + +
E. coli DSM 502 10 – 100 > 70 blue to violet + +
Citrobacter freundii ATCC 8090 10 – 100 > 70 salmon to red + _
Enterobacter aerogenes ATCC 13408 10 – 100 > 70 salmon to red + _
Klebsiella pneumoniae ATCC 13883 10 – 100 > 70 salmon to red + _
Salmonella Enteritidis ATCC 13076 10 – 100 not limited colorless _ _
Enterococcus faecalis ATCC 19433 1,000 – 2,000 < 0.01
Bacillus cereus ATCC 11778 1,000 – 2,000 < 0.01
Ordering Information
Description Order No. Pack Size
Chromocult® Coliform Agar 1.10426.0500 500 g
E. coli/Coliform Selective Supplement 1.00898.0010 1 x 10 vials
Buffered Peptone Water (BPW) 1.07228.0500 500 g
1.07228.5000 5 kg
Sodium chloride peptone broth (buffered) 1.10582.0500 500 g
1.10582.5000 5 kg
Chromoplate® Coliform Agar 1.10156.0001 20 plates
Escherichia coli ATCC 11775 Citrobacter freundii ATCC 8090
Additives
KOVACS Indole reagent 1.09293.0100 100 ml
Bactident® Indole 1.11350.0001 30 ml
Literature
American Public Health Association Kilian, M. and Bülow, P.
1995. Standard methods for the examination of water and wastewater. 19th ed. Rapid diagnosis of Enterobacteriaceae. I. Detection of bacterial glycosidases. Acta
American Public Health Association, Washington, D.C., USA. Pathol. Microbiol. Scand. Sect. B 84: 245 – 251 (1976).
Byamukama, D., Mach, R.L., Kansiime, F., Manai, M. and Farnleitner, A.H. New Zealand Dairy Industry
2005. Discrimination Eficacy of Fecal Pollution Detection in Differen Aquatic Habitats Microbiological Methods Manual, Section 48: Product Test Methods – Enteric Indicator
of a High-Altitude Tropical Country. Using Presumptive Coliforms, Escherichia coli. and Organisms. NZTM 2; 48.5.1 – 48.5.10 (1998).
Clostridium perfringens Spores. Appl. Environ. Microbiol. 71:65 – 71. Ogden, I.D., Brown, G.C., Gallacher, S., Garthwaite, P.H., Gennari, M., Gonzalez,
Geissler, K., Manai, M., Amoros, I. and Alonso, J.L. M.P., Jorgensen, L.B., Lunestad, B.T., MacRae, M., Nunes, M.C., Petersen, A.C.,
2000. Quantitative determination of total coliforms and Escherichia coli in marine Rosnes, J.T. and Vliegenthart, J.
waters with chromogenic and luorogenic media. J. Appl. Microbiol. 88:280 – 285. 1998. An interlaboratory study to ind an alternative to the MPN technique for
Gonzales, R.D., Tamagnini, L.M., Olmos, P.D. and de Sousa, G.B. enumerating Escherichia coli in shellish. International Journal of Food Microbiology
2003. Evaluation of a chromogenic medium for total coliforms and Escherichia coli 40:57 – 64.
determination in ready-to-eat foods. Food Microbiology 20:601 – 604. Ossmer, R., Schmidt, W. and Mende, U.
ISO International Standardisation Organisation 1999. Chromocult® Coliform Agar – Inluence of Membrane Filter Quality
Microbiology of food and animal feeding stuffs – General rules for microbiological on Performance. – XVII Congresso de la Sociedad, Granada, Spain.
examinations. ISO 7218:1996/Amendment 1: 2001. Suwansonthichai, S. and Rengpipat, S.
ISO International Standardisation Organisation 2003. Enumeration of coliforms and Escherichia coli in frozen black tiger shrimp
Microbiology of food and animal feeding stuffs – Preparation of test samples, initial Penaeus monodon by conventional and rapid methods. International Journal of Food
suspension and decimal dilutions for microbiological examination. Part 1: General rules Microbiology 81:113 – 121.
for the preparation of the initial suspension and decimal dilutions. ISO 6887 – 1:1999. Turner, K.M., Restaino, L. and Frampton, E.W.
ISO International Standardisation Organisation 2000. Eficacy of Chromocult Coliform Agar for Coliform and Escherichia coli Detection
Water quality – Sampling. Part 1: Guidance on the design of sampling programmes and in Foods. J. of Food Prot. 63:539 – 541.
sampling techniques. ISO 5667-1: 2006. US-EPA approved method
ISO International Standardisation Organisation Federal Register/Vol. 67, No. 209, 29. October 2002, Rules and Regulations.
Water quality – Gerneral guidance on the enumeration of micro-organisms by culture. U.S. Food and Drug Administration
ISO 8199: 2005. 2003. Bacteriological Analytical Manual Online, Chapter 1: Food Sampling and
Preparation of Sample Homogenate, AOAC International, Gaithersburg, MD., USA.
We provide information and advice to our customers on application technologies and regulatory matters to the best of our know-
ledge and ability, but without obligation or liability. Existing laws and regulations are to be observed in all cases by our custom-
ers. This also applies in respect to any rights of third parties. Our information and advice do not relieve our customers of their own
responsibility for checking the suitability of our products for the envisaged purpose.
For more information on our products:
www.merckmillipore.com/biomonitoring
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