(AB) Fraser Broth 500G

Fraser Broth Base was first described by Fraser and Sperber and is used for the rapid detection of Listeria from food and environmental samples. Peptones and yeast extracts supply necessary growth nutrients. The phosphate salts supply buffering capacity. The addition of esculin and ferric ammonium citrate detect esculin hydrolyzing bacteria (Listeria). The broth is made selective by the addition of antibiotics and other agents. Lithium chloride inhibits Enterococcus sp. which also hydrolyze esculin. Nalidixic acid inhibits the growth of Gram negative microorganisms and acriflavine inhibits Gram positive microorganisms. Fraser Broth Base is used for the selective enrichment of Listeria monocytogenes. (Alpha Biosciences # F06-102-500gm)

Use: Fraser Broth Base is used for the selective enrichment of Listeria monocytogenes.

Description: Fraser Broth Base was first described by Fraser and Sperber and is used for the rapid detection of Listeria from food and environmental samples. Peptones and yeast extracts supply necessary growth nutrients. The phosphate salts supply buffering capacity. The addition of esculin and ferric ammonium citrate detect esculin hydrolyzing bacteria (Listeria). The broth is made selective by the addition of antibiotics and other agents. Lithium chloride inhibits Enterococcus sp. which also hydrolyze esculin. Nalidixic acid inhibits the growth of Gram negative microorganisms and acriflavine inhibits Gram positive microorganisms.

Formula* per Liter:

• Casein Digest Peptone ........... 5.0g
• Pancreatic Digest of Animal Tissue.... 5.0g
• Beef Extract .............................. 5.0g
• Sodium Chloride ................................. 20.0g
• Yeast Extract ............................. 5.0g
• Monopotassium Phospate ................. 1.35g
• Disodium Phosphate ............... 9.6g
• Acriflavine .......................................... 0.024g
• Esculin ....................................... 1.0g
• Lithium Chloride .................................... 3.0g
• Nalidixic Acid.......................... 0.20g

Final pH: 7.2 ± 0.2 at 25.0°C

* Grams per liter may be adj. or formula supplemented to obtain desired performance

Preparation: Mix 55 grams of medium in one Liter of purified water until evenly dispersed Place flask in 50.0°C water bath for 15 minutes and mix occasionally to dissolve completely. Do not overheat while dissolving medium. Distribute and autoclave for at 121.0°C for 15 minutes. Cool to room temperature. Aseptically add 10 mL of a filtered sterilized 5% aqueous solution of ferric ammonium citrate.

Quality Control Specifications:

1. The powder is homogeneous, free flowing and light beige.
2. Visually the prepared base is golden yellow with an opalescent top and clear to light hazy.
3. Expected cultural response after 24-48 hours at 35.0°C.

Organism                                                                      Result

Escherichia coli ATCC 25922                                       Inhibited

Listeria monocytogenes ATCC 7644                             Growth

Staphylococcus aurous ATCC 25923                           Inhibited

Storage: Store the sealed bottle containing the dehydrated medium at 2 to 8.0°C. Once opened and recapped, place the container in a low humidity environment at the same storage temperature. Protect it from moisture and light. The dehydrated medium should be discarded if it is not free flowing or if the color has changed from the original light beige color.