Fraser Half-Broth Strength

Half-Fraser broth is a selective enrichment broth for the identification and isolation of Listeria spp., primarily from food and environmental samples.

The antibiotics, nalidixic acid and acriflavine, are already included in the formulation so only ferric ammonium citrate need be added to make the complete Half-Fraser broth.

The peptones provide carbon, nitrogen and vitamins, sodium chloride provides osmotic balance and the phosphate buffer system maintains pH.

Lithium chloride inhibits enterococci and the antibiotics make the medium highly selective.Listeria spp. hydrolyse aesculin to aesculetin which forms a confirmatory dark brown or black complex with Fe3+ ions.

For the identification and isolation of Listeria spp., primarily from food and environmental samples.

Additional Information

Shelf Life (days): 1095 days

Storage Temp (C): 10-30C

Dehydrated Medium Appearance: Fine Powder

Prepared Medium Appearance: Liquid

Dehydrated Medium Colour: Straw

Prepared Medium Colour: Yellow

Dehydrated PH: 7.2±0.2

Prepared PH: 7.2±0.2

Recommended Incubation: Aerobically at 30C 1C for 18-24 hours

Formula*g/L

Enzymatic digest of animal tissue: 5

Enzymatic digest of casein: 5

Meat extract: 5

Yeast extract: 5

Sodium chloride: 20

Di-sodium hydrogen phosphate: 9.6

Potassium dihydrogen phosphate: 1.35

Aesculin: 1

Lithium chloride: 3

Nalidixic acid: 0.01

Acriflavin: 0.0125

Total: 55