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Thermo Scientific™ Oxoid™ Listeria Selective Oxford Agar Base (Dehydrated)
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Specifications:
| Application | Microbiology | ||
| Storage Temperature | Ambient | ||
| Product Type | Culture Medium | Forms | Powder |
| Product Brand | Thermo Fisher Scientific™, Oxoid | ||
| Product Grade | Microbiology grade | ||
Selective Plating Medium for the Isolation of Listeria monocytogenes from Food and Environmental Samples (FDA/BAM, ISO Compliant)
Thermo Scientific™ Oxoid™ Listeria Selective Oxford Agar Base (CM0856B) is a dehydrated culture medium specifically formulated for the selective isolation and differentiation of Listeria monocytogenes in food and environmental testing, when used in combination with Modified Listeria Selective Supplement (Oxford) SR0206. This medium is specified in key reference standards, including the FDA/Bacteriological Analytical Manual (BAM), AFNOR, IDF, ISO, and USDA protocols.
The agar base utilizes a combination of aesculin and ferric iron as a differential indicator system and selective agents to inhibit background flora, making it ideal for detecting Listeria monocytogenes, especially in complex food matrices.
Key Features & Benefits
- Highly Selective – Suppresses Gram-negative bacteria and most unwanted Gram-positive flora
- Differentiation via Aesculin Hydrolysis – Listeria monocytogenes produces brown colonies with black halos
- Regulatory Approved – Used in FDA/BAM, ISO 11290, and AFNOR-certified testing workflows
- Reliable Performance – Enables clear visual distinction of target colonies in food and environmental surveillance
- Flexible Use – Suitable for routine food testing laboratories, public health labs, and industrial QC
Product Specifications
| Attribute | Details |
|---|---|
| Product Name | Listeria Selective Oxford Agar Base |
| Catalog Number | CM0856B |
| Brand | Thermo Scientific™ Oxoid™ |
| Quantity | 500 g |
| Form | Dehydrated powder |
| Yield | Approximately 8 liters of prepared medium |
| Recommended Supplement | Modified Listeria Selective Supplement (Oxford) SR0206 |
| Certifications/Compliance | FDA BAM, ISO 11290, AFNOR, IDF, USDA |
| Storage | Store in a dry environment at 10–30°C |
| Appearance (Prepared) | Brown agar medium with opaque consistency |
| Shelf Life | As stated on product label |
How It Works
- Aesculin is hydrolyzed by Listeria monocytogenes, forming dark iron phenolic compounds in the presence of ferrous iron, resulting in characteristic black halos around colonies.
- Selective agents in the supplement (e.g., cycloheximide, acriflavine, and colistin sulfate) inhibit Gram-negative and most non-target Gram-positive organisms.
- Some enterococci and staphylococci may exhibit weak growth or aesculin-negative colonies.
Typical Colony Morphology
| Organism | Colony Appearance |
|---|---|
| Listeria monocytogenes | Small, brown colonies with black halos |
| Escherichia coli | No growth (completely inhibited) |
| Enterococcus faecalis | Poor growth, faint blackening (after 40 h) |
| Staphylococcus aureus | Growth possible, aesculin-negative |
Incubation typically at 35–37°C for 24–48 hours.
Ordering Information
| Product | Catalog No. | Quantity |
|---|---|---|
| Listeria Selective Oxford Agar Base (Powder) | CM0856B | 500 g (8 L yield) |
Combine with SR0206 (Modified Listeria Selective Supplement) to complete the medium formulation.
Storage & Safety
- Storage: 10–30 °C in a dry, cool environment
- Precautions: For laboratory use only. Refer to SDS before handling
- Disposal: Dispose of according to local biosafety and chemical waste guidelines
The Thermo Scientific™ Oxoid™ Listeria Selective Oxford Agar Base is a trusted, ISO-compliant culture medium that provides high selectivity and differential properties for the isolation of Listeria monocytogenes in food safety and environmental monitoring. When used with its corresponding supplement (SR0206), it ensures compliance with international regulatory standards, making it an essential component in accredited microbiology laboratories worldwide.