Oxoid™ One Broth Listeria Base 500g Each

Oxoid ONE Broth-Listeria: Rapid Enrichment for Listeria Species

Oxoid ONE Broth-Listeria is an innovative and selective enrichment broth designed for the rapid detection of Listeria species in food samples within just 24 hours. This novel formulation carefully balances a mix of peptones, carbohydrates, and salts, ensuring optimal resuscitation, recovery, and robust growth, even when Listeria spp. are present in very low numbers.

Required Supplement: This product necessitates the use of ONE Broth-Listeria Supplement, Part No. SR00234E.

Typical Formulation:

• Peptone: 26g/L

   

• Carbohydrate mix: 6g/L

   

• Salt mix: 10g/L

   

• Final pH: 7.4 ±0.2 at 25°C

   

Appearance:

• Dehydrated medium: Presents as a straw-coloured, free-flowing powder.

   

• Selective supplement: An orange/yellow, freeze-dried pellet.

• Prepared medium: A dark straw-coloured, clear liquid.

Formulation Directions:

1. Suspend 22g of ONE Broth-Listeria Base in 500ml (equivalent to 44g/L) of distilled water.

    

2. Mix thoroughly, then sterilize by autoclaving at 121°C for 15 minutes.

    

3. Cool the prepared medium to below 50°C.

    

4. Aseptically add the entire contents of one vial of ONE Broth-Listeria Selective Supplement (Mfr. No. SR0234), reconstituted as per its specific directions.

Testing Protocol:

1. Add 25g of the food sample to 225mL of the prepared ONE Broth-Listeria. Stomach the mixture for a minimum of 30 seconds to ensure proper sample mixing.

    
    

2. Incubate the broth without agitation at 30°C for 24 hours.

    

3. Gently agitate the bag. Then, using a microbiological loop, transfer 10μL of the sample onto a suitable agar medium (e.g., Brilliance Listeria Agar, Mfr. No. CM1080, SR0222, and SR0228).

4. Incubate the agar plate appropriately (typically 37°C for 24-48 hours).

5. Confirm any presumptive colonies on the agar plates as Listeria monocytogenes or Listeria spp. using appropriate confirmatory methods. Examples include Gram-stain, catalase, oxidase tests, Oxoid Listeria Latex Test Kit (Mfr. No. DR1126), Oxoid O.B.I.S. mono (Mfr. No. ID0600), or Microbact Listeria 12L (Mfr. No. MB1128).