Liofilchem® ESC Swab with Demi Fraser Broth, 10mL

The Liofilchem ESC (Easy Surface Checking) Swab – Demi Fraser Broth is a ready-to-use device designed for microbiological surface monitoring using the swab sampling method. It incorporates Demi Fraser Broth (Half Fraser Broth), a selective enrichment medium recommended for the detection and enumeration of Listeria monocytogenes and other Listeria species from food, animal feed, and environmental samples.

This system is particularly suitable for environmental monitoring programs (EMP), post-sanitation verification, and carcass sampling in food production facilities, slaughterhouses, and quality control laboratories operating under ISO standards.

Principle of the Method

Demi Fraser Broth supports the selective enrichment and presumptive detection of Listeria spp. through a combination of nutritional, differential, selective, and neutralizing components.

Nutritional Base

The medium contains:

• Peptic digest of animal tissue
• Peptic digest of casein
• Beef extract
• Yeast extract

These provide essential nitrogen, carbon, vitamins, and minerals to support the recovery of stressed or low-level Listeria cells.

Differential System

Ferric ammonium citrate and esculin act as differential agents. All Listeria species hydrolyze esculin to aesculetin, which reacts with ferric ions to produce a black coloration in the medium. Blackening indicates presumptive presence of Listeria spp.

Selective Agents

Selectivity is achieved through:

• Lithium chloride
• Nalidixic acid
• Acriflavine
• Elevated sodium chloride concentration

These inhibit competing microflora while allowing selective enrichment of Listeria spp.

Neutralizing Agents

To ensure accurate environmental monitoring in disinfected areas, the formulation includes:

• Histidine
• Lecithin
• Polysorbate 80
• Sodium thiosulfate

These neutralize residual disinfectants that may otherwise inhibit bacterial recovery.

Product Configuration

Each sterile device consists of:

• A transparent plastic tube containing 10 mL Demi Fraser Broth
• A sterile swab attached to a screw cap

Presentation

Each package includes 100 ready-to-use units and one instruction sheet.

Test Procedure Summary

1. Unscrew the cap with the attached sterile swab.
2. Press the swab tip against the tube wall to remove excess liquid.
3. Swab the target surface horizontally and vertically while rotating the swab.
   A 10 × 10 cm sampling template (100 cm²) may be used where required.
4. Return the swab to the tube and securely close.
5. Label with sampling point and date.
6. Transport to the laboratory and process according to ISO 11290 methods.

Quality Control

Each production batch is quality-controlled using the following strains:

• Listeria monocytogenes serovar 4b WDCM 00021
• Escherichia coli WDCM 00013
• Enterococcus faecalis WDCM 00009

Quality control procedures comply with ISO 11133 requirements for culture media performance testing.

Applications

• Environmental monitoring in food processing plants
• Carcass sampling in slaughterhouses
• Dairy and ready-to-eat food facilities
• HACCP verification programs
• Detection and enumeration of Listeria spp. according to ISO standards

Storage Conditions

Store at 10–25°C, protected from light, until the expiry date indicated on the label.

Do not use if signs of deterioration or contamination are evident.

Safety and Handling

The product does not contain hazardous substances above regulatory classification limits. It is intended for use by trained laboratory personnel. Consult the Safety Data Sheet for proper handling procedures.

Regulatory and Standard Compliance

• ISO 18593: Surface sampling method
• ISO 17604: Carcass sampling for microbiological analysis
• ISO 11290-1: Detection of Listeria monocytogenes and Listeria spp.
• ISO 11290-2: Enumeration of Listeria monocytogenes and Listeria spp.
• ISO 11133: Performance testing of culture media

The Liofilchem ESC Swab – Demi Fraser Broth provides a standardized, ISO-compliant solution for surface microbiological monitoring and selective enrichment of Listeria spp. Its integrated neutralizers, differential blackening reaction, and ready-to-use format make it an efficient and reliable tool for quality assurance laboratories and food safety programs.