CRITERION™ BAIRD-PARKER AGAR BASE

Cat. no. C5080 CRITERION™ Baird-Parker Agar Base 126gm
Cat. no. C5081 CRITERION™ Baird-Parker Agar Base 500gm
Cat. no. C5082 CRITERION™ Baird-Parker Agar Base 2kg
Cat. no. C5083 CRITERION™ Baird-Parker Agar Base 10kg
Cat. no. C5084 CRITERION™ Baird-Parker Agar Base 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Baird-Parker Agar Base is prepared with Egg Yolk Tellurite Enrichment for a selective medium for the detection and enumeration of coagulase-positive staphylococci from food samples.(1)

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.

SUMMARY

Baird-Parker Medium was developed by Baird-Parker to isolate and enumerate coagulase-positive staphylococci from foods.(3) The present formulation, by Baird-Parker, is a modification from a previous formula developed by Zebovitz, Evan, and Niven.(4) Sodium pyruvate was added as a selective growth stimulant, and egg yolk emulsion as a differentiation agent. The medium allows growth of Staphylococcus aureus and selectively inhibits growth of most other bacteria.

Selective inhibition is thought to be caused by the combination of the selective agents tellurite and lithium. Glycine and pyruvate are added to enhance the growth of staphylococci.

After 24 to 48 hours of incubation at 35-37ºC., colonies of S. aureus will appear black, convex, shiny, and 1-1.5mm in diameter. The very distinct black colonies formed by S. aureus are a result of the reduction of tellurite in the medium. These colonies will normally be surrounded by clear zones, a result of proteolysis or lipolysis. Occasionally, opaque zones will form within this clear zone, a result of lipase or lecithinase activity. Other bacteria which may grow on this medium are easily distinguished from S. aureus, as they do not form black colonies.

FORMULA*

Baird-Parker Agar Base:
Gram weight per 940ml: 63.0gm
Glycine 12.0gm
Pancreatic Digest of Casein 10.0gm
Sodium Pyruvate 10.0gm
Beef Extract 5.0gm
Lithium Chloride 5.0gm
Yeast Extract 1.0gm
Agar 20.0gm

Egg Yolk Tellurite Enrichment:
Egg Yolk Emulsion 50.0ml/L
Potassium Tellurite Solution, 1% 10.0ml/L

Final pH 7.0 +/- 0.2 at 25ºC.

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

STORAGE AND SHELF LIFE

Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original light tan.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 63.0gm of the dehydrated culture media in 940.0ml of distilled or deionized water.

2. Heat to boiling and mix to dissolve completely.

3. Sterilize in the autoclave at 121ºC. for 15 minutes.

4. Cool to 45-50ºC.

5. Aseptically add 10mL of a sterile 1% potassium tellurite solution and 50.0mL of sterile egg yolk emulsion.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, consult listed references or refer to the prepared media Instructions for Use (IFU) for Cat. No. G96.

LIMITATIONS

Coagulase-negative staphylococci generally do not grow well on Baird-Parker Agar; if some growth occurs, the typical clear zones are absent. Proteus or Bacillus species may also grow but appear as brown colonies.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, and incubators, etc., are not provided.

QUALITY CONTROL

Test Organisms
Inoculation Method*
Incubation
Results
Time
Temperature
Atmosphere
Staphylococcus aureus
ATCC ® 25923
A 24hr 35°C Aerobic Growth; black shiny colonies with clear halo
Proteus mirabilis
ATCC ® 12453
A 24hr 35°C Aerobic Growth; brown colonies
Escherichia coli
ATCC ® 25922
B 24hr 35°C Aerobic Partial to complete inhibition

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Baird-Parker Agar Base powder should appear homogeneous, free-flowing, and light tan in color. The prepared media, with supplement, should appear opaque, and light yellow in color.

REFERENCES

1. AOAC. Association of Official Analytical Chemists, Official Methods of Analysis, AOAC, Washington, D.C.

2. Baird-Parker. 1962. J. Appl. Bact.; 25:12.

3. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

4. Zebovitz, Evan, et al. 1955. J. Bact.; 70:686.


ATCC is a registered trademark of the American Type Culture Collection.

050916gr