Listeria Half-Fraser Broth with Ferric Ammonium Citrate ISO is a selective medium designed for the primary enrichment of Listeria monocytogenes and other Listeria species. This formulation follows the ISO 11290 standard and is optimized for the recovery of stressed or sublethally injured Listeria cells from food, environmental, and clinical samples.
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2225 Listeria Half-Fraser Broth with Ferric Ammonium Citrate ISO, Condalab
2225
Condalab
This medium is a modification of the full-strength Fraser Broth, containing half the concentration of selective agents (Nalidixic Acid and Acriflavine) to facilitate the repair and growth of damaged Listeria cells. The base contains Enzymatic Digests of Casein and Animal Tissue, Beef Extract, and Yeast Extract, providing a rich source of nitrogen, vitamins, and minerals. Lithium Chloride is included to inhibit the growth of Enterococci. This specific version already contains Ferric Ammonium Citrate within the powder, simplifying the laboratory workflow. The differentiation is based on Esculin hydrolysis: Listeria spp. produce esculetin, which reacts with the iron ions to turn the broth black, serving as a presumptive indicator of contamination.
Advantages
- Optimized Recovery: The "Half-Fraser" formula is specifically designed to recover injured Listeria cells during the critical primary enrichment phase.
- ISO Standard Compliance: Formulated in accordance with ISO 11290 for the detection and enumeration of Listeria.
- Simplified Preparation: Inclusion of Ferric Ammonium Citrate in the dehydrated base reduces the number of supplements to be added manually.
- High Selectivity: Effectively suppresses background flora (Gram-negative and most Gram-positive bacteria) that could interfere with the detection of the pathogen.
- Clear Visual Indicator: The blackening of the medium provides a reliable presumptive signal for the presence of Listeria species.
Technical specifications
| Catalogue number | 2225 |
| Brand | Condalab |
| Application | Primary enrichment of Listeria monocytogenes (ISO 11290) |
| Typical Composition (g/L) | Enzymatic Digest of Casein (5.0); Enzymatic Digest of Animal Tissues (5.0); Beef Extract (5.0); Yeast Extract (5.0); Lithium Chloride (3.0); Sodium Chloride (20.0); Esculin (1.0); Ferric Ammonium Citrate (0.5); Phosphates (13.35) |
| Final pH (at 25 °C) | 7.2 ± 0.2 |
| Preparation | 57.85 g/L (Add Half-Fraser Selective Supplement) |
| Storage Temperature | 2 – 25 °C |
Available packaging options
| 2225 | 500 g plastic bottle |
| Brand | Condalab |
| Pack size | 500 g |
