74 DIFGOMANUAL 



To rehydrate the medium, suspend 60 grams Bacto-Tomato Juice Agar 

 Special in 1000 ml. cold distilled water. Heat to boiling to dissolve the medium 

 completely. Distribute in tubes or flasks and sterilize in the autoclave for 15 

 minutes at 15 pounds pressure (121°C.). Overheating of this acid medium is to 

 be avoided to prevent hydrolysis of the agar giving a soft medium. Final reaction 

 will be pH 5.0. 



One pound of Bacto-Tomato Juice Agar Special will make 7.5 liters of 

 medium. 



1 Bacteriology and Immunology of Dental 2 Dentistry in Public Health, 1949. 



Caries and Dental Science and Dental 

 Art, 1938. 



BACTO 



TRYPSIN DIGEST AGAR (B30) 



DEHYDRATED 



Trypsinized Milk (800 ml.) 20 g. 



Tomato Juice (200 ml.) 10 g. 



Bacto-Peptone 8 g, 



Bacto-Dextrose 4 g. 



Dextrin, Difco 4 g. 



Bacto-Agar 13 g. 



Bacto-Trypsin Digest Agar is recommended for the plate count and cultiva- 

 tion of Lactobacillus acidophilus. By using a tryptic digest of milk, to which 

 tomato juice and other nutriments were added. Dr. H. A. Cheplin was able to 

 secure excellent growth of L. acidophilus. 



Bacto-Trypsin Digest Agar readily lends itself to use in isolating strains of 

 L. acidophilus as well as for carrying them in stock. It is an excellent plate 

 medium for determining the relative numbers of organisms in acidophilus prod- 

 ucts and for estimating the degree of intestinal implantation. 



Bacto-Trypsin Digest Agar is prepared according to the formula specified by 

 Dr. Cheplin. Results obtained with this dehydrated medium when it is made up 

 for use are comparable to those secured when the medium is prepared from 

 ingredients. 



To rehydrate the medium, suspend 59 grams of Bacto-Trypsin Digest Agar in 

 1000 ml. of cold distilled water and heat to boiling to dissolve the medium com- 

 pletely. Distribute in tubes or flasks and sterilize in the autoclave for 15 minutes 

 at 15 pounds pressure (121°C.). The final reaction of the medium will be pH 

 6.1. 



One pound of Bacto-Trypsin Digest Agar will make 7.6 liters of medium. 



BACTO 



SKIM MILK (B32) 



DEHYDRATED 



Bacto-Skim Milk is high grade skim milk reduced to powder by the spray 

 process. It is readily soluble and is easily prepared for use. Bacto-Skim Milk is 

 recommended for use with Bacto-Tryptone Glucose Extract Agar in the prepara- 

 tion of the Tryptone Glucose Extract Milk Agar according to "Standard 

 Methods for the Examination of Dairy Products."^ It is also recommended for 

 the preparation of skim milk solutions used in the propagation of organisms 

 occurring in milk products, and to demonstrate coagulation and proteolysis of 



