Biokar

Half Fraser broth

Reference : BM01608

CAD$78.83

Half-Fraser broth is used for the selective and differential (primary enrichment broth) enrichment of Listeria monocytogenes and of Listeria spp. in food products, according to the Standard NF EN ISO 11290-1.

The media is also used in the context of alternative rapid methods for the detection and enumeration of Listeria monocytogenes or Listeria spp.

Available in 10 vials of 225 ml

In compliance with regulatory requirements, a USDA permit (VS 16-3) is mandatory for shipments from Canada to the USA due to the inclusion of peptone, an animal byproduct.

Available format:

10 vials of 225 ml

QUANTITY

Formulation:

- Enzymatic digest of animal tissues............................................................................5.0 g

- Enzymatic digest of casein ......................................................................................5.0 g

- Yeast extract..........................................................................................................5.0 g

- Meat extract...........................................................................................................5.0 g

- Sodium chloride.....................................................................................................20.0 g

- Disodium phosphate, anhydrous*.............................................................................. 9.6 g

- Monopotassium phosphate........................................................................................ 1.35 g

- Esculin ....................................................................................................................1.0 g

- Lithium chloride........................................................................................................3.0 g

- Nalidixic acid........................................................................................................... 10.0 mg

- Acriflavine hydrochloride......................................................................................... 12.5 mg

- Ferric ammonium citrate..............................................................................................0.5 g

The very satisfactory recovery of Listeria monocytogenes is assured by the concentration differences in nalidixic acid and acriflavine between Half-Fraser and Fraser, as well as the two enrichment steps themselves. Half-Fraser Broth is used for the primary enrichment step, while Fraser Broth is used for secondary enrichment.

Polypeptone, yeast extract and meat extract furnish the nutrients required for the growth of Listeria. The high sodium chloride content increases the selectivity of the medium. Phosphates act as buffers and maintain the pH of the medium.

Esculin is hydrolyzed by Listeria to glucose and esculetin, the latter compound forming a black complex with ferric ions supplied by ferric citrate, added just before use, which also favors the growth of Listeria. Lithium chloride inhibits the growth of most enterococci which can also hydrolyze esculin. Nalidixic acid blocks the DNA replication of bacteria sensitive to this antibacterial agent. The growth of secondary Gram-positive microflora is inhibited by acriflavine.

A needle connector (Instantplug) is used for the efficient transfer of InstantBag media through a Gravimetric Dilutor or other peristaltic system.

Reference BM01608

Brand: Biokar