CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



577 



1845. Bacto Conradi-Drigalski Agar 

 (Dehydrated) 



Constituents: 



1. Distilled water. 



2. Peptone, Bacto 10.0 g. 



3. Sodium caseinate, Bacto. . 10.0 g. 



4. Lactose, Bacto 10.0 g. 



5. Agar, Bacto 15.0 g. 



6. NaCl 5.0 g. 



7. Dibromcresolsulphoneph- 



thalein 0.03 g. 



8. Crystal violet 0.02 g. 



Preparation : 



(1) Dissolve 50.0 g. of Bacto Conradi- 

 Drigalski Agar (dehydrated) in 1000.0 

 cc. of distilled water by boiling or 

 autoclaving. 



(2) Restore any lost weight. 



(3) If sterilized at 15 pounds pressure for 

 20 minutes pH = 6.8±. 



Sterilization: Sterilize at 15 pounds pres- 

 sure for 20 minutes. 



Use: The author reported that acid produc- 

 ing colonies were yellow. 



Reference: Digestive Ferments Co. (1925 

 p. 12). 



1846. Haner and Frost's Milk Agar 



Constituents : 



1. 1.0% nutrient agar (De- 

 hydrated Difco) 1000.0 cc. 



2. Milk, sterile 1000.0 cc. 



Preparation : 



(1) Prepare 1.0% agar from dehydrated 

 Difco product. 



(2) Add an equal part of sterile milk to 

 sterile (1). 



Sterilization: Method not given. 

 Use: Cultivation of staphylococci. 

 Reference: Haner and Frost (1921 p. 270). 



1847: Eldredge and Roger's Whey Agar 



Constituents : 



1. Whey 1000.0 cc. 



2. Lactic acid (10.0%) 20.0 cc. 



3. Peptone (1.0%) 10.0 g. 



4. Beef extract (5.0%) 50.0 g. 



5. Agar (1.2%) 12.0 g. 



Preparation : 



(1) Heat one liter of skim milk to boiling 

 and add 20.0 cc. of a 10.0% lactic acid 

 solution. 



(2) Filter. 



(3) Add 1.0% peptone, 5.0% beef extract 

 and 1.2% agar to the filtrate. 



(4) Heat to boiling point until all the 

 agar is dissolved. 



(5) Correct the reaction to 1.2 using 

 phenolphthalein as an indicator. 



(6) Cool to 45°C. and add the whites of an 

 egg. 



(7) Heat to lOO^C. for 45 minutes and 

 filter thru cotton. 



(8) Correct the reaction if necessary and 

 tube. 



Sterilization : Sterilize three successive days 



in the Arnold sterilizer. 

 Use: Cultivation of bacteria found in 



cheese. Author reported that bulgaricus 



types grew well on this medium. 

 Reference: Eldredge and Rogers (1914 



p. 8). 



1848. Ayres and Mudge's Milk Powder 

 Agar 



Constituents: 



1. Water 500.0 cc. 



2. Skimmed milk powder. 5.0 g. 



3. Na.HPOi + 2HoO 

 (Sorensen's phosphate). 1.0 g. 



4. Peptone (Difco) 2.0 or 5.0 g. 



5. Liebig's extract 1.0 or 3.0 g. 



6. Agar 3.0% 500.0 cc. 



Preparation : 



(1) Pour 5.0 g. skimmed milk powder 

 into 20.0 cc. cold distilled water. 

 Stir until dissolved. 



(2) Dissolve by heat, 1.0 g. Sorensen's 

 phosphate in 5.0 cc. distilled water. 



(3) Add (2) to (1), place in 30°C. water 

 bath and heat to 60° in 10 minutes. 

 A flocculent grayish precipitate 

 appears. 



(4) Steam until precipitate gets white. 



(5) Dilute about \ with distilled water 

 and steam 5 more minutes. 



(6) Decant solution and filter, keeping 

 most of the precipitate in beaker 

 until most of the liquid has passed 

 thru the filter. Then wash precipi- 

 tate with a little distilled water. 

 The filtrate is cloudy. 



(7) Make up (6) to 250.0 cc. with dis- 

 tilled water. 



(8) Dissolve 5.0 g. peptone and 3.0 g. 

 Liebig's extract in 100.0 cc. distilled 



