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Fraser Broth

Fraser Broth is used with Acriflavin, Nalidixic Acid, and Ferric Ammonium Citrate for the selective enrichment of Listeria spp. in a laboratory setting. Fraser Broth is not intended for use in the diagnosis of disease or other conditions in humans.

Listeria monocytogenes, described first in 1926 by Murray, Webb and Swann, is an extensive problem in food industries. Evidence from outbreaks of listeriosis indicated the principle route of transmission is via the consumption of foodstuffs contaminated with Listeria monocytogenes. Implicated vehicles of transmission include turkey frankfurters, coleslaw, pasteurized milk, Mexican style cheese and pate.

Fraser Broth is based on the formulation of Fraser and Sperber. This medium is used in rapid detection of Listeria from food and environmental samples. Listeria spp. grow over a pH range of 5.0 – 9.6, and survive in food products with pH levels outside these parameters. Listeria spp. are microaerophilic, Gram-positive, asporogenous, non-encapsulated, non-branching, short, motile rods. Motility is pronounced at 20°C. Identification of Listeria spp. is based on successful isolation of the organism, biochemical characterization, and serological confirmation.

 

Formula Liter
Enzymatic Digest of Casein 5 g
Enzymatic Digest of Animal Tissue 5 g
Beef Extract 5 g
Yeast Extract 5 g
Sodium Chloride 20 g
Disodium Phosphate 12 g
Monopotassium Phosphate 1.35 g
Esculin 1 g
Lithium Chloride 3 g

Final pH: 7.2 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications.

Supplement / 10 mL

Acriflavin, 25 mg
Nalidixic Acid, 20 mg

Supplement / 5 mL

Ferric Ammonium Citrate, 250 mg

Directions

  1. Dissolve 57.4 g of the medium in one liter of purified water.
  2. Stir without heat to obtain solution, if necessary, warm to 50°C. DO NOT OVERHEAT.
  3. Autoclave at 121°C for 15 minutes. Cool broth to room temperature.
  4. Aseptically add 10 mL of a filter sterilized solution containing 20 mg Nalidixic Acid and 25 mg Acriflavin. Additionally, add 2 x 5 mL Ferric Ammonium Citrate Supplement (7984).

Order Details

Product # Product Description
7626A Fraser Broth, 500 g
7626T Fraser Broth, 5 kg