BUFFERED PEPTONE WATER

Technical Data #2482a / 2013.06.15

Buffered Peptone Water is used as a pre-enrichment medium for the isolation of Salmonella sp. from foods products. Food preservation techniques such as heat, dessication, preservatives or pH changes can affect Salmonella sp. This pre-enrichment maintain a high pH for 24 hours and repair compromised microorganisms.

 


 

FORMULA
in grams per liter purified filtered water

Gelatin Peptone

10,0

Sodium Chloride

5,0

Sodium Phosphate, dibasic

3,5

Potassium Phosphate, monobasic

1,5

pH 7,2 +/- 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 (evaporation or discoloration) Do not use dehydrated media if it is caked.


DIRECTIONS

Suspend 20 g in 1000 ml of purified water. Heat with frequent agitation and boil for one minute. Dispense into culture tubes or 50 ml per bottle. Sterilize at 121° C for 15 minutes.


PROCEDURE
Bring prepared medium at room temperature before inoculation.

  1. Aseptically, inoculate 10 grams of the specimen.
  2. Incubate at 35° C for 24 hours.
  3. Subculture to Mac Conkey Agar Plate (#1517) for lactose and non-lactose fermenters growth
  4. Subculture to Hektoen Agar Plate (#1882) for non-lactose fermenters growth
  5. Incubate at 35° C for 24 hours.
  6. Examine for growth of lactose or non-lactose fermenters.


QUALITY CONTROL

Expected results after 24 hrs at 35ºC

Organisms

ATCC

Growth

Salmonella typhimurium

14028

+

Escherichia coli

25922

+


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


REFERENCES

  1. Mac Faddin, Jean F. 1985 Media for Isolation-Cultivation Identification-Maintenance of Medical Bacteria. Vol. I, Baltimore, MD.: Williams & Wilkins.
  2. Poelma, P.L., J.H. Silliker 1976 Compendium of methods for the microbiological examination of foods. A.P.H.A.:302-304 Washington, D.C.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-2104
     
Prepared media    
Tubes 16x125 mm, 5 ml 10/pkg 2482
Bottle 99ml 10/pkg 5252
Plates, Mac Conkey Agar, 100x15mm 10/pkg 1517
Plates, Hektoen Agar, 100x15mm 10/pkg 1882

 


 

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