INGREDIENTS OF CULTURE MEDIA 293 



Phenol Red Broth Base, Bacto-Phenol Red Agar Base, Bacto-Purple Broth 

 Base and Bacto-Purple Agar Base as discussed on pages 186-190. The following 

 carbohydrate solutions are supplied in packages of one-half dozen or one dozen 

 ampuls of 10 ml. each: 



Dextrose Solution 10% (B155A) Maltose Solution 10% (B168A) 

 Galactose Solution 10% (B163A) Mannitol Solution 10% (B170A) 

 Glycerol Solution 10% (B282A) Saccharose Solution 10% (B176A) 



Lactose Solution 10% (B156A) 



DYES AND INDICATORS 



Dyes and indicators are essential to the preparation of most differential culture 

 media. In such media the dyes may act as bacteriostatic agents, as inhibitors of 

 growth or as indicators of changes in the degree of acidity or alkalinity of the 

 substrate. It is obvious, therefore, that only dyes of known purity and known 

 dye content should be used in the preparation of media. 



Great care is necessary in the preparation of differential or selective media, 

 even with dyes standardized by the most modern methods. All ingredients of the 

 medium must be used in the amounts specified in the formula and the reaction 

 of the medium must be adjusted with extreme care in order to obtain proper 

 results. Certain of the dyes listed in this section are identified by their Color 

 Index number (C.I. No.) according to "Color Index" of the Society of Dyers 

 and Colourists, 1924. The actual dye content of each dye is shown on each label. 



BAGTO-BASIG FUGHSIN (B191) 

 For Endo Agar and Other Basic Fuchsin Media 



Bacto-Basic Fuchsin (C.I. No. 676) is certified for use in culture media and 

 for the general histological and bacteriological staining by the Commission on 

 Standardization of Biological Stains. 



Bacto-Basic Fuchsin is recommended for the preparation of Endo Agar and 

 other basic fuchsin media. In Endo Agar this dye is partially decolorized with 

 sodium sulfite. On this medium lactose fermenting organisms form red colonies 

 and change the color of the surrounding medium from faint pink to red; typical 

 Escherichia coli colonies, in addition to being red in color, generally exhibit a 

 brilliant metallic sheen. Organisms not fermenting lactose form uncolored 

 colonies which do not alter the appearance of the medium. 



In Tryptose Agar, discussed on page 111, Bacto-Basic Fuchsin may be em- 

 ployed in a concentration of 1:100,000 for differentiation of strains of Brucella. 

 In Bacto-Fuchsin Lactose Broth, discussed on page 41, the dye is present in a 

 concentration of 1 : 66,000. 



BAGTO-BRILLIANT GREEN (B192) 



For Brilliant Green Media 



Bacto-Brilliant Green (C.I. No. 662) is certified for use in culture media by 

 the Commission on Standardization of Biological Stains. 



Bacto-Brilliant Green is recommended for use in preparing the Brilliant 



