CRITERION™ BACILLUS CEREUS AGAR BASE

Cat. no. C5060 CRITERION™ Bacillus Cereus Agar Base 82gm
Cat. no. C5061 CRITERION™ Bacillus Cereus Agar Base 500gm
Cat. no. C5062 CRITERION™ Bacillus Cereus Agar Base 2kg
Cat. no. C5063 CRITERION™ Bacillus Cereus Agar Base 10kg
Cat. no. C5064 CRITERION™ Bacillus Cereus Agar Base 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Bacillus Cereus Agar Base is a selective agar medium used for the isolation and determination of Bacillus cereus .

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

Holbrook and Anderson described a highly selective and diagnostic medium (PEMBA) for the isolation and determination of Bacillus cereus from food. (1) The medium is formulated to detect small numbers of contaminates. Colonies of B. cereus growing on this medium can readily be identified by microscopic examination. The addition of sodium pyruvate enhances egg yolk precipitation and sporulation. Mannitol-fermentation is detected by the pH indicator bromothymol blue. Selective activity is produced by the addition of polymyxin B at a concentration of 100,000 units per liter. (2,3) In the event of high mold content, cycloheximide (40mg/L) can be added.

FORMULA

Gram weight per liter: 41.0gm/L
Mannitol 10.0gm
Sodium Pyruvate 10.0gm
Disodium Phosphate 2.5gm
Sodium Chloride 2.0gm
Peptic Digest of Animal Tissue 1.0gm
Dipotassium Phosphate 250.0mg
Bromothymol Blue 120.0mg
Magnesium Sulfate 100.0mg
Agar 15.0gm

Final pH 7.2 +/- 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 off-white.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 41.0gm of the dehydrated culture media in 950ml of distilled or deionized water.

2. Heat to boiling and mix to dissolve completely.

3. Distribute and sterilize in the autoclave at 121ºC. for 15 minutes.

4. Cool to 45-50ºC. and aseptically add enrichments (50ml of a sterile egg yolk suspension and 2ml of a filtered solution of polymyxin B (100,000units). If required, cycloheximide may be added at a concentration of 40mg/L.

5. Mix thoroughly and dispense.

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. G156.

LIMITATIONS

On this medium, B. cereus is indistinguishable from B. thuringiensis .

Occasional strains of B. cereus shows weak or negative egg yolk reactions.

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
Bacillus cereus
ATCC ® 13061
A 24-48hr 35°C Aerobic Growth; blue colonies with blue precipitate halos
Bacillus subtilis
ATCC ® 6633
B 24-48hr 35°C Aerobic Partial to complete inhibition; media remains yellow
Pseudomonas aeruginosa
ATCC ® 27853
B 24-48hr 35°C Aerobic Inhibited

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ Bacillus Cereus Agar Base powder should appear homogeneous, free-flowing, and off-white in color. The prepared media should appear clear to a trace hazy, and blue in color.

REFERENCES

1. Can. 1980. J. Microbiol.; 26:753-7590.

2. Donovan, K.O. 1958. J. Appl. Bacteriol.; 21(1):100-103.

3. Mossel, D.A.A., et al. 1967. J. Appl. Bacteriol.; 15(3):650-653.

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

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

050916gr