CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



(3) Obtain the casein and thoroly press 



it dry. 



(4) Rub the casein to a powder and wash 

 with 95.0% alcohol, and place in a 

 flask of ether. 



(5) Shake for 2 minutes and allow to 

 stand for 18 minutes. 



(6) Pour off the ether and add fresh. 

 Repeat this process 3 or 4 times. 



(7) Pour off but half the last portion of 

 the ether and add alcohol (amount 

 not specified). 



(8) Shake for 5 minutes. 



(9) If drops of fat raise when alcohol is 

 added, repeat the washing of the 

 casein with ether until the casein is 

 fat-free. 



(10) Collect the casein on a filter. 



(11) Dry and heat for 5 to 20 minutes at 

 120 to 140°C. 



(12) Wash in a moderately concentrated 

 alkali solution. 



(13) This gives a transparent material, 

 which when dry becomes hard as 

 stone. This casein will dissolve by 

 heating in slightly alkaline water. 



(14) Prepare 150.0 cc. of an 8.0% solution 

 of (13). 



(15) Mix 350.0 cc . of filtered whey contain- 

 ing 1.75% agar with (14). 



(16) Heat for 15 to 20 minutes at 60 or 

 70°C. Do not boil or the casein will 

 be coagulated. 



(17) Distribute in sterile test tubes. 

 Sterilization: Not specified. 



Use : Cultivation or pathogenic organisms. 

 References: Raskin (1887 p. 359), Peifer 

 (1888 p. 568). 



2162. Stutzer and Hartleb's Whey Agar 



Constituents : 



1. Whey 1000.0 cc. 



2. Agar 20.0 g. 



Preparation : 



(1) Separate the cream from milk by 

 centrifugation. 



(2) Heat to 40°C. and add a little rennet. 



(3) After the casein has coagulated heat 

 to 75°C. and filter. 



(4) To a liter of (3) add 20.0 g. of finely 

 chopped agar and heat in the steamer 

 for 1.5 to 2.0 hours. 



(5) Neutralize by adding soda (indicator 

 not specified). 



(6) Medium may be employed with a 

 neutral, basic, (by adding Na2C03), or 

 acid, (by adding lactic acid), reaction. 



Sterilization: Not specified. 



Use: Stutzer and Hartleb attempted to 

 cultivate the bacterium causing foot and 

 mouth disease. Other investigators used 

 similar media for the cultivation of a 

 large number of organisms. 



Variants : 



(a) Huss cultivated aroma producing 

 bacteria, Bacillus esterificans and 

 Pseudomonas trifolii on a medium 

 prepared by dissolving 20.0 g. agar 

 and 5.0 g. NaCl in 1000.0 cc. of whey. 



(b) Meier made bacterial counts of milk 

 and milk products in a medium pre- 

 pared as follows: 



(1) Dissolve 2.5 g. NaCl and 15.0 or 

 (10.0 g.) agar in 500.0 cc. of water. 



(2) Mix equal parts (1) and whey. 



(3) Neutralize by the addition of 

 KOH. Add KOH until tumeric 

 paper is turned quite weakly brown- 

 ish-red. 



(4) Sterilization not specified. 



(c) Fulmer and Grimes used the following 

 medium for the cultivation of yeast 

 found in cream and butter. 



(1) Dissolve 1.5% agar in whey ob- 

 tained from skim milk by coagulat- 

 ing the casein with rennet. 



(2) Filter (1) thru absorbent cotton. 



(3) Tube in 10.0 cc. portions. 



(4) Sterilize for 20 minutes at 15 pounds 

 pressure. 



(5) When using as a plate medium, add 

 1.0 cc. of a 1.0% tartaric acid solu- 

 tion to each Petri dish to keep down 

 bacterial growth. 



(d) Klimmer and Sommerfeld (Klimmer) 

 made bacterial counts of milk on a 

 medium prepared as follows: 



(1) Prepare clear agar solution using 

 20.0 g. agar, 7.0 g. NaCl and 1000.0 

 cc. water. 



(2) Sterilize (1) method not given. 



(3) Add a little rennet to milk obtained 

 under the cleanest possible con- 

 ditions and heat at 40°C. until the 

 casein is coagulated. 



(4) Separate the casein from the whey 

 by straining thru a straining cloth. 



