EC Broth was originally developed by Hajna and Perry to improve the recovery of coliforms and E. coli while suppressing interfering non-coliform bacteria. The medium contains bile salts, which are highly effective at inhibiting Gram-positive organisms and some Gram-negative bacteria other than coliforms. Lactose serves as the fermentable carbohydrate source, and the strong buffering system (potassium phosphates) ensures pH stability for optimal growth. The medium is specifically formulated for elevated temperature incubation (44.5 °C), which allows for the differentiation of "fecal" coliforms from the wider coliform group.
Advantages
- High Selectivity: Specifically optimized to inhibit competitive microflora at elevated temperatures.
- Reliable E. coli Detection: Standardized for use in the confirmed test phase of the MPN method for fecal coliforms.
- NutriSelect® Plus Quality: Premium-grade medium offering high sensitivity and batch-to-batch consistency for regulated testing.
- Robust Buffering: Contains a phosphate buffer system to maintain the pH during rapid fermentation of lactose.
- Global Compliance: Formulated in accordance with APHA and AOAC recommendations for water and food analysis.
Interpretation of Results
| Microorganism |
Growth (at 44.5 °C) |
Gas Production |
| Escherichia coli |
Luxuriant |
Positive (+) |
| Klebsiella aerogenes |
Variable to inhibited |
Negative or delayed |
| Enterococcus faecalis |
Inhibited |
Negative (-) |
| Staphylococcus aureus |
No growth |
Negative (-) |
Technical specifications
| Catalogue number |
44653 |
| Brand / Product Line |
Sigma-Aldrich / NutriSelect® Plus |
| Typical Composition (g/L) |
Tryptose or Casein peptone (20.0); Lactose (5.0); Bile salts mixture (1.5); Dipotassium phosphate (4.0); Monopotassium phosphate (1.5); NaCl (5.0) |
| pH (at 25 °C) |
6.9 ± 0.2 |
| Preparation |
37.0 g/L |
| Storage Temperature |
15 – 25 °C |
Available packaging options
| 44653-500G |
500 g plastic bottle |
