CHROMagar™ E.coli Chromogenic Medium

For Detection and Enumeration of Escherichia coli in Water, Food, and Environmental Samples

CHROMagar™ E. coli is a selective chromogenic culture medium specifically designed for the detection, enumeration, and presumptive identification of Escherichia coli as an indicator of faecal contamination in food, water, and environmental samples. On this medium, E. coli colonies develop a distinctive intense blue coloration, enabling accurate and rapid colony counting—even at low concentrations.

Validated for membrane filtration, surface streaking, and pour plate techniques, CHROMagar™ E. coli provides a sensitive, easy-to-read solution for monitoring hygiene and compliance with international microbiological standards in drinking water, bathing water, processed foods, and environmental surfaces.

🔹 Key Features & Benefits

• ✅ Clear Colony Color Differentiation:
  • E. coli: Intense blue colonies for easy and accurate enumeration.
• ✅ Rapid Results: Detectable and countable colonies in just 24 hours.
• ✅ Enhanced Medium Strength: Contains 5% more agar than conventional media for optimal surface firmness—ideal for membrane filtration and sample streaking.
• ✅ Improved Workflow: Simplifies E. coli screening compared to traditional multi-step methods (e.g., MPN), significantly reducing time and labor.
• ✅ Versatile Testing Methods: Suitable for:
  • Direct surface plating
  • Membrane filtration (ISO 9308-1)
  • Pour plate method

🔹 Colony Appearance

🔹 Intended Use

CHROMagar™ E. coli is intended for:

• Quantitative detection and enumeration of E. coli in:
  • Drinking and recreational water (ISO 9308-1)
  • Food and beverage products
  • Wastewater and environmental samples
• Use in:
  • HACCP plans
  • Food and water safety monitoring
  • Public health microbiology laboratories

⚠️ Not intended to diagnose infections in clinical specimens or guide antimicrobial therapy. Confirmatory testing may be required.

🔹 Regulatory Context & Public Health Significance

The presence of E. coli is a primary indicator of faecal contamination, and therefore a potential warning sign for other dangerous pathogens such as Salmonella, Vibrio cholerae, Pseudomonas spp., viruses, and parasites.

Regulatory limits include:

• EU Directive (2006/7/EC): ≤ 500 E. coli CFU/100 mL in bathing water
• Drinking water standards: Zero-tolerance for E. coli per 100 mL
• Food standards typically require 0–10 CFU/g depending on product type and process stage

📌 CHROMagar™ E. coli enables fast and reliable monitoring of these critical hygiene parameters.

🔹 Test Procedure

1. Sample Types: Water (drinking, bathing), food products, surface rinses
2. Inoculation Methods:
   • Direct streaking
   • Membrane filtration
   • Pour plating
3. Incubation:
   • Temperature: 37 °C
   • Time: 18–24 hours
   • Atmosphere: Aerobic
4. Interpretation:
   • E. coli = blue colonies
   • Other organisms = inhibited or non-distinct

🔹 Ordering Information

🔹 Storage & Shelf Life

• Storage Conditions: 2–8 °C, sealed and protected from light
• Shelf Life: Up to 24 months when stored as recommended
• Prepared Plates: Follow manufacturer’s guidelines for use-by period

🔹 Scientific Publications

• Alonso J. L. et al. (1996) – Quantitative determination of E. coli in water using CHROMagar™ E. coli
  (J. Microbiol. Methods, 25: 309–315)
• Grand M. et al. (1996) – Comparison with official methods for E. coli enumeration
• Weissman S. (1994) – Comparison with MPN method in Israel

CHROMagar™ E. coli is an efficient, easy-to-use solution for reliable detection and enumeration of Escherichia coli across a wide range of matrices. Its blue chromogenic colony differentiation, high performance in various plating techniques, and compliance with international standards make it an indispensable tool for food safety, water quality assurance, and environmental monitoring.