FRASER BROTH SUPPLEMENT

Cat. no. Z210 Fraser Broth Supplement, 100ml Serum Bottle, 100ml 1 bottle

INTENDED USE

Hardy Diagnostics Fraser Broth Supplement is used with Half Fraser Broth Base for the selective enrichment and detection of Listeria spp. This supplement is also used in conjunction with Fraser Broth Base for the detection of Listeria monocytogenes from food and environmental samples.

This product is not intended to be used for the diagnosis of human disease.

SUMMARY

First described by Murray, Webb, and Swann, Listeria monocytogenes is a widespread problem in public health and food industry. (6,8) This microorganism can cause human illness and death, particularly in immunocompromised individuals and in the unborn fetus of pregnant women. The first reported food-borne outbreak of listeriosis was in 1985. Since then, microbiological and epidemiological evidence from both sporadic and epidemic cases of listeriosis has shown that the principal route of transmission is via the consumption of foodstuffs contaminated with Listeria monocytogenes . (7,10)

Potential vehicles of transmission implicated in the spread of disease include turkey frankfurters, coleslaw, pasteurized milk, Mexican-style and other soft cheeses, pate, and pickled pork tongue. Moreover, the organism has been isolated from commercial dairy and other food processing plants. It is ubiquitous in nature, being present in a wide range of unprocessed foods, in soil, sewage, silage, and river water. Listeria also possess the ability to grow over a pH range of 5.0-9.6 and can survive in food products with pH levels outside of these parameters. (10)

Hardy Diagnostics Fraser Broth Base is based on the formulation of Fraser and Sperber. (7) It contains pancreatic digest of casein, proteose peptone, and yeast extract as nitrogen, vitamin, and mineral sources. Hardy Diagnostics Half Fraser Broth Base is a modification of Fraser Broth Base in which the nalidixic acid and acriflavine concentrations have been reduced to 10.0mg/L and 12.5mg/L. The supplementation of Hardy Diagnostics Fraser Broth Base aids in differentiation by including ferric ammonium citrate in the final medium. Since all Listeria species hydrolyze esculin, the addition of ferric ions to the medium will detect the reaction. Ferric ions, combined with esculetin, produce a dark brown to black color change in the medium surrounding the colonies.

Selectivity of Fraser Broth and Half Fraser Broth is provided by the presence of lithium chloride, nalidixic acid, and acriflavine in the formula. The high salt tolerance of Listeria is used as a means to inhibit growth of enterococci.

FORMULA

Ingredients per liter of deionized water:*

Ferric Ammonium Citrate 5.0gm

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Storage: Upon receipt store at 2-8ºC. away from direct light. Media should not be used if there are any signs of deterioration, discoloration, contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.

PRECAUTIONS

METHOD OF PREPARATION FOR PREPARED CULTURE MEDIA

1. Suspend 55.0gm of the dehydrated culture media (Fraser Broth Base, Cat. no. C5780 or Half Fraser Broth Base, Cat. n. C8040) in 1 liter of distilled or deionized water.

2. Heat, while stirring to dissolve completely. Avoid overheating.

3. Dispense in appropriate containers and autoclave at 121ºC. for 15 minutes.

4. Cool to room temperature. Aseptically add enrichment, 10ml of a filter sterilized 5% aqueous solution of ferric ammonium citrate (Fraser Broth Supplement, Cat. no. Z210).

5. Dispense as desired into sterile containers.

PROCEDURE

Consult listed references for information regarding sample preparation and processing. (4,7,8,10)

To isolate Listeria monocytogenes from processed meats and poultry, the following procedure is recommended by the U.S.D.A:

1. Add 25.0gm of test material to 225ml Modified Listeria Enrichment Broth and mix or blend thoroughly.

2. Incubate for 20-24 hours at 30ºC.

3. Transfer 0.1ml of the incubated broth to the prepared Fraser Broth. Incubate at 35ºC. for 26 +/- 2.0 hours.

4. At 24 and 48 hours, streak the prepared Fraser Broth culture to Modified Oxford Agar.

5. Incubate the Modified Oxford plates at 35ºC. for 24-48 hours.

INTERPRETATION OF RESULTS

Examine plates for typical Listeria colonies. Listeria monocytogenes will appear as clear colonies surrounded by a blackening in the media.

LIMITATIONS

Fraser Broth Supplement is not an isolation medium. This product is used in conjunction with Fraser Broth Base or Half Fraser Broth Base.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, Fraser Broth Base (Cat. no. C5780), Half Fraser Broth Base (Cat. no. C8040), incinerators, and incubators, etc., as well as serological and biochemical reagents are not provided.

QUALITY CONTROL

Fraser Broth Supplement is not a growth medium. It is tested for sterility only.

USER QUALITY CONTROL

PHYSICAL APPEARANCE

Fraser Broth Supplement should appear clear, and dark brown in color.

REFERENCES

1. American Public Health Association. Standard Methods for the Examination of Dairy Products, APHA, Washington, D.C.

2. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the Microbiological Examination of Foods, APHA, Washington, D.C.

3. Grau, F.H., et al. 1995. Occurrence, numbers, and growth of Listeria monocytogenes on some vacuum-packaged processed meats. J. Food Prot. ; 55:4-4.

4. International Dairy Federation. 1990. Milk and milk products - detection of Listeria monocytogenes . IDF Provisional International Standard No. 143. International Dairy Federation, Brussels, 1990.

5. Kramer, P.A., et al. 1969. Media selective for Listeria monocytogenes . J. Appl. Bacteriology ; 32:381-394.

6. Lovett, J.D., et al. 1987. Listeria monocytogenes J. Food Prot. ; 50:188-192.

7. Monk, J.D, et al. 1987. Irradiation inactivation of Listeria monocytogenes and Staphylococcus aureus in low and high-fat frozen and refrigerated ground beef. J. Food Prot ., 57:769-772.

8. Murray, E.G, et al. 1926. A disease of rabbits characterized by large mononuclear leucocytosis caused by ahitherto undescribed bacillus Bacterium monocytogenes . J. Path. Bact. ; 19:407-439.

9. U.S. Food and Drug Administration. Bacteriological Analytical Manual. AOAC, Arlington, VA. www.fda.gov/Food/ScienceResearch/LaboratoryMethods/BacteriologicalAnalyticalManualBAM/default.htm

10. Vanderzant, C. and D.F. Splittstoesser, (ed.). 1992. Compendium of Methods for the Microbiological Examination of Foods, 3rd ed. APHA, Washington, D.C.

11. Wehr, H.M. 1987. Listeria monocytogenes - a current dilemma Special Report. J. Assoc. Anal . Chem. ; 80:769-7762.


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