Thermo Scientific™ Oxoid™ ONE Broth-Listeria Supplement

The Oxoid ONE Broth-Listeria Supplement is a freeze-dried selective additive used in conjunction with the Oxoid ONE Broth-Listeria Base (Part No. CM1066) for the selective enrichment of Listeria species from food samples. This supplement ensures optimal growth, recovery, and resuscitation of Listeria spp., including Listeria monocytogenes, within a 24-hour incubation period, making it ideal for food microbiology testing and quality control applications.

Key Features

1. Selective Enrichment:
   • Enhances the selectivity of ONE Broth-Listeria for isolating Listeria spp. in complex food samples.
2. Rapid Turnaround:
   • Facilitates the detection of Listeria species within 24±2 hours, streamlining testing workflows.
3. Optimized Formulation:
   • Freeze-dried pellets ensure long shelf life and easy reconstitution for consistent results.
4. High Yield:
   • Available in two formats:
     • SR0234B: Each vial prepares 2.25L of medium.
     • SR0234E: Each vial prepares 500mL of medium.

Specifications

Formulation Directions

1. Suspend 22g of ONE Broth-Listeria Base in 500mL of distilled water (final concentration 44g/L).
2. Mix thoroughly and sterilize by autoclaving at 121°C for 15 minutes.
3. Cool the medium to below 50°C.
4. Reconstitute the freeze-dried ONE Broth-Listeria Supplement (SR0234) as directed and aseptically add to the cooled broth.

Testing Protocol

1. Sample Preparation:
   • Add 25g of food sample to 225mL of prepared ONE Broth-Listeria medium.
   • Homogenize (stomach) the sample for at least 30 seconds.
2. Incubation:
   • Incubate the broth at 30°C for 24±2 hours without agitation.
3. Plating:
   • After incubation, gently agitate the sample.
   • Using a microbiological loop, inoculate 10μL of the broth onto a selective agar medium such as:
     • Brilliance Listeria Agar ISO (Mfr. No. CM1212, SR257, SR0258).
   • Incubate plates at 37°C for 24-48 hours.
4. Confirmation:
   • Confirm presumptive colonies as Listeria monocytogenes or Listeria spp. using methods like:
     • Gram staining.
     • Catalase and oxidase tests.
     • Oxoid Listeria Latex Test Kit (Mfr. No. DR1126).
     • Additional confirmation tools such as:
       • Oxoid O.B.I.S. mono (Mfr. No. ID0600).
       • Microbact Listeria 12L (Mfr. No. MB1128).

Applications

1. Food Microbiology:
   • Detection and isolation of Listeria spp. in food products, including raw materials, processed foods, and ready-to-eat items.
2. Research:
   • Study of Listeria spp. recovery and growth dynamics.
3. Quality Assurance:
   • Ensuring compliance with food safety standards by testing for Listeria monocytogenes contamination in food production environments.

Advantages

• Efficiency: Reduces time to result to 24 hours for rapid decision-making in food safety workflows.
• Sensitivity: Recovers low levels of Listeria spp., including stressed and injured cells.
• Ease of Use: Freeze-dried form simplifies preparation and ensures consistency across batches.

References

• ISO 11290-1: Microbiology of food and animal feeding stuffs — Horizontal method for enumeration of Listeria monocytogenes.
• Oxoid Brilliance Listeria Agar protocols (Mfr. Nos. CM1212, SR257, SR0258).
• Oxoid Poster - Folio No. 1033, July 2004.

For laboratory use only, the Oxoid ONE Broth-Listeria Supplement is an essential component for high-accuracy Listeria detection in food microbiology testing.