Validation of the AquaCHROM^TM ECC for the Detection and Enumeration of Coliforms and Escherichia coli in Water Samples: AOAC Performance Tested Method^SM 072202.

This article focuses on the validation of the AquaCHROM™ ECC method, developed by CHROMagar, for the detection and enumeration of Escherichia coli and coliform bacteria in 100 mL water samples, including tap, well, lake, and bottled water. The method uses a non-agar-based chromogenic powder medium that produces green to blue-green coloration for E. coli and yellow for non-E. coli coliforms after 18–24 hours of incubation at 35–37 °C, allowing results to be read under normal lighting without UV light. Validation studies, conducted under AOAC INTERNATIONAL guidelines and including inclusivity/exclusivity testing, product consistency, robustness, and independent laboratory matrix comparisons, demonstrated that AquaCHROM ECC is statistically equivalent to U.S. Environmental Protection Agency (EPA) Method 1604 and FDA Bacteriological Analytical Manual (BAM) Chapter 4 for detection and enumeration of these bacteria. The method offers a simpler workflow without filtration or additional confirmation steps and provides accurate results within 24 hours, supporting its use as an effective alternative for microbiological water quality testing.