CULTURE MEDIA FOR CULTIVATION OF MICROORGANISMS 



659 



(8) Heat at 50°C. until all the liquid has 

 evaporated. 



(9) Heat at 100 to 105°C. for one hour. 



(10) Pound to a powder. 



(11) Dissolve 6.0 g. (10), 3.0 g. of NaCI 

 and 22.0 g. agar in a liter of water 

 by heating in the steamer. 



(12) Add 10.0% soda solution until the 

 reaction is 0.05 to 0.07% alkaline. 



(13) Boil for another hour in the steamer. 



(14) Allow to stand over night at room 

 temperature. 



(15) Cut away the bottom of the agar 

 containing the sediment. 



(16) Melt the clear agar and flask. 

 Sterilization: Sterilize on each of 3 suc- 

 cessive days in the steamer for 1.5 hours. 



Use: General culture medium. 



Variant: Klimmer used 10.0 g. (10), 8.0 g. 



NaCl, 0.1 g. KNO3, 22.0 g. agar and 0.2 g. 



Na2C03 in a liter of water instead of the 



quantities given above. 

 Reference: Klimmer (1923 p. 171). 



2047. Jensen's Milk Digest Agar 



Same as medium 1112, but solidified 

 with agar. 



2048. Bacto Nutritive Caseinate Agar 

 (Dehydrated) 



Constituents : 



1. Distilled water 1000.0 cc. 



2. Peptonized milk Bacto 7.0 g. 



3. Sodium caseinate 3.0 g. 



4. Agar 12.0 g. 



Preparation: 



(1) Dissolve 22.0 g. of Bacto Nutritive 

 Caseinate Agar (Dehydrated) in 

 1000.0 cc. distilled water by boiling. 



(2) If sterilized at 15 pounds for 20 min- 

 utes pH = 6.5±. 



Sterilization: Sterilize in the autoclave at 

 15 pounds pressure for 20 minutes. 



Use: For differential and comparative milk 

 counts. 



Reference: Digestive Ferments Co. (1925 

 p. 13). 



2049. Bacto Peptonized Milk Agar 

 (Dehydrated) 



Constituents: 



1. Distilled water 1000.0 cc. 



2. Peptonized milk 15.0 g. 



3. Agar, Bacto 12.0 g. 



Preparation : 



(1) Dissolve 27.0 g. of Bacto Peptonized 

 Milk Agar (Dehydrated) in 1000.0 cc. 

 distilled water by boiling or auto- 

 claving. 



(2) Restore lost weight if necessary. 



(3) If sterilized at 15 pounds pressure 

 for 20 minutes pH = 6.5±. 



Sterilization: Sterilize in the autoclave at 

 15 pounds pressure for 20 minutes. 



Use: For bacteriological examination of 

 dairy products. 



Reference: Digestive Ferments Co. (1925 

 p. 14). 



2050. Cole and Onslow's Trypsinized Casein 

 Agar 



Solidify medium 1130 with agar. The 

 agar is added at step (18). (See me- 

 dium 1130.) 



2051. Teruuchi and Hida's Trypsinized 

 Casein Agar 



Constituents: 



1. Water 1000.0 cc. 



2. Casein 100.0 g. 



3. NasCOa (10.0% soln.) 



4. Pancreatin 



5. NaCl (0.5%) 



6. Agar (2.0%) 

 Preparation : 



(1) Dissolve 100.0 g. of pure casein in 

 1 liter of 0.8% NajCOa (anhydrous). 



(2) Add 5.0 to 10.0 g. of pancreatin 

 (Gehe and Co.) and shake with 

 chloroform. 



(3) Place for 3 to 5 days in the incubator, 

 shaking occasionally. 



(4) Each day test the mixture for trj^pto- 

 phane, by adding a few drops of 

 acetic acid to a sample and then 

 adding bromine water. 



(5) When the tryptophane content has 

 reached its maximum and the tyro- 

 sine has separated out as white 

 clumps, heat the fluid for a short 

 time at 80°C. 



(6) Filter and neutralize with a few cc. 

 of HCl. 



(7) Heat moderately, in a vacuum if 

 possible, and evaporate to a syrupy 

 thickness. (Possibly may be fil- 

 tered again.) 



