VIOLET RED BILE AGAR

Technical Data #1480a / 2013.07.03

Violet Red Bile Agar is a solid medium used for the detection and isolation of coliforms in food, water, milk and sanitary material.
Bile salts and crystal violet are the inhibitors of gram-positive microorganisms. Lactose fermenting coliforms give red colonies with precipitation of bile salts.

 


 

FORMULA
in grams per liter purified filtered water

Casein Peptone

7,0

Bile Salts #3

1,5

Yeast Extract

3,0

Lactose

10,0

Sodium Chloride

5,0

Neutral Red

0,03

Crystal Violet

0,002

Agar

15,0

pH 7,4 +/- 0,2 25 C

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


PRECAUTIONS
This medium is for IN VITRO diagnostic 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 42 g of dehydrated media in 1000 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. Mix gently and dispense into sterile Petri dishes.


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

  1. Directly, inoculate plate as soon as possible with specimen and streak for isolation.
  2. Incubate at 35 C for 24 hours.


QUALITY CONTROL

Results after 24 hrs at 35C

Organisms

ATCC

Growth

Colour
Escherichia coli

25922

+

red, bile point

Enterobacter aerogenes

13048

+

pinkish

Salmonella typhimurium

14028

+

colorless

Streptococcus faecalis

29212

-

 

Staphylococcus aureus

25923

-

 


LIMITATIONS OF METHOD
Selectivity may decrease after 24 hours incubation. 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.1. Baltimore, MD.: Williams & Wilkins.
  2. Standard Methods for the Examination of Dairy Products, 13th Ed. APHA, N.Y. 1972
  3. Standard Methods for the examination of Water and Wastewater 1985 16th Ed. APHA, Washington, D.C.


CATALOGUE NUMBERS

Dehydrated media 500 grams QB-39-5601
Prepared media    
Plates, 100x15 mm 10/pkg 1480
Mono-Plates, 100x15 mm 10/pkg 1480M

 


 

 

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