BACILLUS CEREUS AGAR

Technical Data #1426a / 2005.08.18

Bacillus Cereus Agar is a solid selective medium for isolation of Bacillus cereus from food in small amount even in presence of large numbers of contaminates. Sodium pyruvate enhances egg yolk precipitation and bromthymol blue is the pH indicator for the mannitol fermentation. Polymixin B is the selective agent.

FORMULA
in grams per liter purified filtered water

Casein Peptone

1,0

Mannitol

10,0

Sodium Chloride

2,0

Magnesium Sulfate

0,1

Sodium Phosphate, dibasic

2,5

Potassium Phosphate, monobasic

0,25

Sodium Pyruvate

10,0

Bromthymol Blue

0,1

Agar

15,0

Supplement

 
Egg Yolk Solution

50 ml

Antibiotic

 
Polymixin B

100 000 units

pH 7,6 +/- 0,2 à 25º C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for laboratory use only.


STORAGE
Store prepared media at 2-8° C protected from direct light and dehydrated powder, in a dry place, in tightly-sealed containers at 2-25° C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Prepared media should not be used if there are signs of contamination or deterioration (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 41 g of dehydrated media in 950 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Sterilize at 121° C for 15 minutes. Cool to 45-50° C. Aseptically add 50 ml of sterile solution of Egg yolk (#8653) and 100 000 units of a sterile solution of Polymixin B. Mix gently and dispense into sterile Petri dishes .


PROCEDURE
Prior to inoculate, the prepared media should be brought to room temperature.

  1. Directly, inoculate the surface of medium with specimen and streak for isolation.
  2. Incubate at 35° C for 24-48 hours.


QUALITY CONTROL
Results after 48 hrs at 35ºC

Organisms

ATCC

Growth

Bacillus cereus

clinical

+ Greenish-blue w/ halo

Proteus mirabilis

12453

+/- w/o halo


LIMITATIONS OF METHOD
This medium is only a part of the identification. Other tests may be required.


REFERENCES

  1. Holbrook, A., J.M. Anderson, 1980 Can. J. Microbiol. 26:753-759
  2. Weasel, D.A.A., M.J. Kaapman, E. Jongerius 1967 App. Microb. 15:650
  3. FDA 1995 Bacteriological Analytical Manual 8th, ed AOAC International
  4. Atlas, R.M., 1997 Handbook of Microbiological Media 2nd, ed L.C. Parks editor


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-0150
     
Egg Yolk Supplement 100 ml 8653
Polymixin B 4 MM units QB-39-3514
     
Prepared media    
Plates, 100x15 mm 10/pkg 1426
Mono-plates, 100x15mm 10/pkg 1426M

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