This medium is formulated to allow the rapid growth of coliform bacteria while suppressing the growth of non-coliform organisms. Selectivity is achieved through sodium lauryl sulfate, which inhibits most Gram-positive bacteria and many non-enteric Gram-negative rods. The medium uses lactose as a fermentable carbohydrate and phenol red as a pH indicator. When coliforms ferment lactose, they produce acid, causing the indicator to change the color of the colonies (or the membrane filter) from red-orange to yellow. As part of the NutriSelect® Plus line, this medium is manufactured to high-purity standards, ensuring excellent recovery and clear differentiation of target pathogens.
Advantages
- Optimized for Membrane Filtration: Specifically tailored for use with absorbent pads in membrane filter procedures.
- High Sensitivity: High-quality peptones ensure the recovery of "stressed" coliforms often found in treated water.
- Sharp Differentiation: The phenol red indicator provides a distinct yellow color change, making colony counting straightforward.
- NutriSelect® Plus Quality: Premium-grade ingredients ensure batch-to-batch consistency and high performance in regulated labs.
- Standardized Formulation: Complies with international recommendations for water quality monitoring.
Interpretation of Results
| Reaction |
Appearance |
Interpretation |
| Positive |
Yellow colonies |
Lactose fermenter (Coliform) |
| Negative |
Red, pink, or colorless colonies |
Non-lactose fermenter |
Technical specifications
| Catalogue number |
07348 |
| Brand / Product Line |
Sigma-Aldrich / NutriSelect® Plus |
| Typical Composition (g/L) |
Peptone (40.0); Yeast extract (6.0); Lactose (30.0); Sodium lauryl sulfate (0.1); Phenol red (0.1) |
| pH (at 25 °C) |
7.4 ± 0.2 |
| Preparation |
76.2 g/L |
| Storage Temperature |
15 – 25 °C |
Available packaging options
| 07348-500G |
500 g plastic bottle |
