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Liofilchem™ Fraser Supplement
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10 vials Supplement A + 10 vials Supplement B
Specifications:
| Application | Microbiology | ||
| Storage Temperature | 2-8°C | ||
| Product Type | Supplement | Forms | Liquid |
| Product Brand | Liofilchem | ||
| Product Grade | Microbiology grade | ||
Selective Enrichment Supplement for Detection of Listeria monocytogenes and Listeria spp. in Food and Environmental Samples (ISO 11290-1)
The Liofilchem® Fraser Supplement is a lyophilized two-part additive used for the selective enrichment and presumptive identification of Listeria monocytogenes and Listeria species from food, feed, and environmental samples. When added to Fraser Broth Base (Refs. 610375, 620375), it forms the complete Fraser Broth medium, compliant with ISO 11290-1 and ISO 11290-2 standards.
This supplement enables selective suppression of background flora through acriflavine and nalidixic acid, while ammonium ferric citrate allows visual confirmation of Listeria growth through aesculin hydrolysis, producing blackening of the medium.
Key Features & Benefits
- ISO 11290-1 Compliant – Validated for official food microbiology testing of Listeria monocytogenes
- Two-Part Supplement – Includes separate vials of antibiotics (Supplement A) and indicator (Supplement B)
- Selective & Differential – Inhibits competing flora while enabling aesculin hydrolysis-based detection
- Reliable Blackening Reaction – Clear visual marker for presumptive Listeria presence
- Pre-measured & Ready-to-Use – Each vial pair prepares 500 mL of Fraser Broth
Product Specifications
| Attribute | Details |
|---|---|
| Product Name | Fraser Supplement |
| Reference Code | 81046 |
| Contents | 10 vials Supplement A + 10 vials Supplement B |
| Form | Lyophilized (freeze-dried) |
| Storage Conditions | 2–8°C, protected from light |
| Shelf Life | 1 year from manufacture |
| Application | Enrichment for detection of Listeria spp. |
| Packaging | 20 vials per kit (10 of A, 10 of B) |
Composition
| Component | Per Vial | Per Liter of Medium |
|---|---|---|
| Supplement A | Acriflavine 12.5 mg | 25 mg |
| Nalidixic acid 10 mg | 20 mg | |
| Supplement B | Ammonium ferric citrate 0.25 g | 0.5 g |
Preparation & Use
- Reconstitute one vial each of Supplement A and Supplement B with 5 mL sterile distilled water.
- Add aseptically to 500 mL of Fraser Broth Base, previously autoclaved and cooled to 45–50°C.
- Mix thoroughly and dispense into sterile containers.
Performance Testing (QC)
| Organism (WDCM) | Growth | Blackening |
|---|---|---|
| Listeria monocytogenes serovar 4b (00021) | Good | + |
| Escherichia coli (00013) | Inhibited | − |
| Enterococcus faecalis (00009) | Partial | − |
Visual inspection: Reconstituted supplements appear clear and limpid.
Compliance & References
- ISO 11290-1:2017 – Detection of Listeria monocytogenes and Listeria spp.
- ISO 11290-2:2017 – Enumeration of Listeria monocytogenes
- EN ISO 11133:2014 – Media preparation and quality assurance
- Fraser & Sperber (1988), J. Food Prot. 51, 762–765
Warnings & Safety
- Contains substances classified as hazardous under current legislation
- For professional use only
- Consult the Safety Data Sheet (SDS) before handling
- Discard if contamination or degradation is evident
Ordering Information
| Product | Reference Code | Pack Size |
|---|---|---|
| Fraser Supplement | 81046 | 20 vials (10 A + 10 B) |
One vial each of Supplement A and B is sufficient for 500 mL of medium.
Liofilchem® Fraser Supplement provides a reliable, selective enrichment system for detecting Listeria monocytogenes and Listeria spp. in food and environmental samples. When used with Fraser Broth Base, it delivers high specificity, consistent aesculin hydrolysis response, and ISO 11290 compliance, making it an essential tool in food safety testing, microbiological monitoring, and regulatory compliance laboratories.