Chromogenic Coliform Agar: A Smarter Approach to Water Testing

Water is one of the most closely monitored resources in public health and food production. Among the many microbiological parameters that can be measured, total coliforms and Escherichia coli (E. coli) remain the most widely accepted indicators of sanitary quality.

Coliform bacteria are naturally present in the environment, while E. coli is more specifically associated with fecal contamination.

Their presence strongly suggests that contamination may have occurred and that corrective actions may be required. 

While coliforms are primarily used as indicator organisms, their presence may suggest treatment failures, contamination within the distribution system, surface water intrusion, sewage infiltration, or inadequate sanitation practices.

The detection of E. coli is of even greater concern, as it signals potential fecal contamination and may be associated with the presence of other potentially harmful microorganisms.

If contaminated water is consumed, individuals may experience symptoms ranging from mild gastrointestinal discomfort, diarrhea, nausea and abdominal cramps to more severe waterborne illnesses in vulnerable populations.

For this reason, routine monitoring of these indicators is an essential component of any water quality and public health protection program.

CCA: Chromogenic Coliform Agar

To simplify the detection of key microbial indicators in water, we offer Chromogenic Coliform Agar (CCA), a selective and differential culture medium developed for the simultaneous detection and differentiation of coliform bacteria and E. coli in water samples.

Widely used with membrane filtration methods, CCA provides clear visual differentiation, simplifying result interpretation and supporting straightforward interpretation of characteristic colony colours in accordance with the applicable method.

Key Advantages of CCA

• Concurrent detection of total coliforms and E. coli on a single plate. 
• Easy interpretation through chromogenic reactions
• Excellent selectivity and recovery of target organisms. 
• Suitable for routine water quality monitoring program. 
• Improved laboratory efficiency and streamlined workflows. 

Reading CCA results

• Non-target bacteria: Tergitol-7 contributes to the selective properties of the medium by inhibiting many non-target microorganisms, helping to facilitate the detection of coliform bacteria and E. coli.
• Coliforms: Coliform bacteria expressing β-D-galactosidase hydrolyse Salmon-GAL, producing distinctive salmon-red colonies.
• E.coli: E. coli expresses both β-D-galactosidase and β-D-glucuronidase, resulting in characteristic dark blue to violet colonies. The presence of tryptophan also enables indole testing for additional confirmation.

Monitoring coliforms and E. coli is essential to ensure water safety, regulatory compliance, and public health protection. If you are looking for a reliable solution for water microbiology testing, contact our team to learn more about Chromogenic Coliform Agar (CCA) and how it can support your laboratory's water monitoring program.