DEHYDRATED CULTURE MEDIA 187 



hydrate by some microorganisms. An entire series of carbohydrate broths may 

 thus be made up readily, conveniently, and economically. 



To rehydrate the medium, dissolve 16 grams of Bacto-Phenol Red Broth Base 

 in 1000 ml. of distilled water. To this solution the test carbohydrate is added 

 in proper quantity, and, when solution is complete, the medium is distributed 

 in fermentation tubes. Sterilize by autoclaving for not more than 15 minutes 

 at 15 pounds pressure ( 121°C.) . The minimum amount of heat required for com- 

 plete sterilization is to be desired. By packing the tubes loosely in the autoclave to 

 allow free circulation of steam, the time required may be appreciably shortened, 

 provided the temperature in the autoclave is actually 121°G. The final reaction 

 of the medium, without added carbohydrate, will be pH 7.4. 



The addition of some carbohydrates may result in an acid reaction. In this 

 case it is suggested that O.IN sodium hydroxide be added drop by drop to restore 

 the original color, taking care not to obtain too deep red or cerise color. 



One pound of Bacto-Phenol Red Broth Base will make 28.3 liters of medium. 



An extensive number of carbohydrates, polyhydric alcohols and glucosides, 

 Difco, are available (see page 291) for use with Bacto-Phenol Red Broth Base. 

 There is also available a selected list of filter-sterilized ampuled solutions of 

 some of these carbohydrates, each ampul containing 10 ml. of a 10 per cent 

 solution, or 1 gram of carbohydrate (see page 292). 



^Diagnostic Procedures and Reagents 3rd Edition: 107: 1950. 



BACTO 



PHENOL RED CARBOHYDRATE BROTHS 



DEHYDRATED 



Complete fermentation media, prepared with Bacto-Phenol Red Broth Base 

 and 0.5 per cent of the more frequently used carbohydrates, are available. The 

 dehydrated media included in this group are: 



BACTO-PHENOL RED DEXTROSE BROTH (B93) 

 BACTO-PHENOL RED LACTOSE BROTH (B94) 

 BACTO-PHENOL RED MANNITOL BROTH (B97) 

 BACTO-PHENOL RED SACCHAROSE BROTH (B95) 

 BACTO-PHENOL RED MALTOSE BROTH (B96) 



To rehydrate the media, dissolve 21 grams of the Bacto-Phenol Red Carbo- 

 hydrate Broth in 1000 ml. distilled water. The complete media are sterilized as 

 described above, using the minimum amount of heat necessary for sterilization, 

 for not more than 15 minutes at 15 pounds pressure (121°C.). The final reaction 

 of these media will be pH 7.4. 



One pound of each complete Bacto-Phenol Red Carbohydrate Broth will make 

 21.6 liters of medium. 



BACTO 



PHENOL RED AGAR BASE (B98) 



DEHYDRATED 



Bacto-Beef Extract 1 g. 



Proteose Peptone No. 3, Difco . . 10 g. 



Sodium Chloride 5 g. 



Bacto-Agar 15 g. 



Bacto-Phenol Red 0.025 g. 



