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

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.

Light beige, homogeneous, free flowing powder.

Yellow, hazy to clear, complete with upper 10% of solution light to medium red upon standing.

7.2±0.2

Escherichia coli ATCC 25922: Inhibited Listeria monocytogenes ATCC 7644: Growth Staphylococcus aurous ATCC 25923: Inhibited

Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

1. Dissolve 55grams per liter of distilled/ deionized (DDI) water, heating with stirring until completely solubilized.

2.Place flask in 50°C water bath for 15 minutes and mix occasionally to dissolve completely. Do not overheat while dissolving medium.

3. Distribute and autoclave for at 121.0°C for 15 minutes. Cool to room temperature.

4. Aseptically add 10 mL of a filtered sterilized 5% aqueous solution of ferric ammonium citrate.

Store powdered media at 4°C. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be stored at 4°C and used within a short period of time.