m-TEC AGAR

Technical Data #1661a / 2013.08.18

m-Tec Agar is a solid medium used for the isolation, differentiation and enumeration of the thermotolerant Escherichia coli by the membrane filter technique from water. Sodium desoxycholate and sodium lauryl sulfate inhibit gram-positive bacteria. Bromcresol purple and bromphenol red are the indicators.

 


 

FORMULA
in grams per liter purified filtered water

Proteose Peptone

5,0

Yeast Extract

3,0

Lactose

10,0

Sodium Chloride

7,5

Dipotassium Phosphate

3,3

Monopotassium Phosphate

1,0

Sodium Lauryl Sulfate

0,2

Sodium Desoxycholate

0,1

Bromcresol Purple

0,08

Bromphenol Red

0,08

Agar

15,0

pH 7,3 +/- 0,2 25 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 45,3 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Autoclave 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. Place the membrane filter used to collect the water sample, on the surface of the agar. Avoid air bubbles between surface of agar and membrane filter.
  2. Seal individual dish with waterproof tape.
  3. Immerge Petri dishes in a water bath at 44,5 C for 24 hours.
  4. Remove from water bath.
  5. Place an absorbent pad in the lid and saturate it with urease substrate. To prepare urease substrate, dissolve 2 g of urea and 10 mg of phenol red in 100 ml of purified filtered water. Adjust pH at 5,0 +/- 0,2
  6. Transfer the membrane filter from the agar to the absorbent pad.
  7. After 15-20 minutes count any of the yellow or yellowish brown colony presumptively identified as Escherichia coli.


QUALITY CONTROL

Results after 24 hrs at 44,5C

Organisms

ATCC

Growth

Colour

Escherichia coli

25922

+

yellow

Escherichia coli

11775

+

yellow

Enterococcus faecalis

29212

-

 


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


REFERENCES

  1. Atlas, R.M Handbook of Microbiological Media 1997 2nd, ed Lawrence C. Parks editor
  2. Standard Methods for Examination of Water and Wastewater 1989 17th ed. APHA Washington D.C.


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-2911
     
Prepared media    
Plates, 100x15 mm 10/pkg 1661
Plates, 60x15 mm 10/pkg 1327

 


 





2325, Dandurand, Suite 300 Phone Fax Internet
Montreal (Quebec) (514) 277-2558 (514) 277-4714 http://www.quelab.com
Canada H2G 1Z9 1 (800) 579-0998 1 (800) 579-8177 info@quelab.com