Dehydrated MacConkey-Agar medium without salt and crystal violet for selective and differential isolation and detection of enteric bacteria including coliforms and pathogens in microbiological testing.
MacConkey-Agar (without salt), catalogue No. 51405, is a dehydrated differential culture medium supplied by MilliporeSigma / Merck under the NutriSelect® Plus quality segment. This formulation omits added sodium chloride and crystal violet, providing a low-selective environment for Gram-negative bacteria. The medium incorporates agar as a solidifying agent, bile salts to suppress Gram-positive organisms, lactose as a fermentable carbohydrate and neutral red as an indicator to differentiate lactose-fermenting coliforms from non-lactose-fermenting bacteria. It is widely used in clinical microbiology, food and beverage quality control and environmental testing laboratories.
Advantages
- Selective differential medium for Gram-negative bacteria including coliforms and pathogens.
- NutriSelect® Plus quality for reliable performance in routine microbiological workflows.
- Formulated without salt and crystal violet to facilitate growth of a broader range of organisms.
- Powdered form allows flexible preparation of culture plates.
- Displays clear differentiation of lactose fermenters versus non-fermenters.
Technical specifications
| Product name | MacConkey-Agar (without salt) |
| Catalogue number | 51405 |
| Brand / quality | NutriSelect® Plus |
| Form | Dehydrated powder |
| Selective agents | Bile salts |
| Indicator | Neutral red |
| Technique | Microbiological culture / differential plating |
| Suitable for | Coliforms; enteric bacteria; *E. coli*, *Salmonella*, *Shigella*, *Proteus* |
| Typical use | Clinical, food, beverage and environmental microbiology |
| Prepared pH | 7.4 ± 0.2 (25 °C) |
| Packaging size | 500 g |
| Storage conditions | 15–25 °C, dry |
| Brand | Merck |
| Pack size | 500 g |
