DEHYDRATED CULTURE MEDIA 37 



adjusted and the medium should not be filtered. The medium is relatively stable 

 and may be stored for short periods of time. It is usually used in petri dishes; 

 however, some laboratories have found tubes to be convenient. The tubes should 

 be prepared with long slants and no butts. 



Levine E.M.B. Agar is prepared according to the formula specified in "Stand- 

 ard Methods for the Examination of Water and Sewage"^ and since 1926 our 

 label has carried a statement to this effect. 



The "Standard Methods for the Examination of Water and Sewage" in the 

 Ninth Edition permits the use of either Endo or Eosin Methylene Blue Agar as 

 solid media for confirming tubes of Lactose Broth showing positive presumptive 

 tests. 



Taft and Daly® prepared a selective medium for the primary isolation of 

 pathogenic intestinal bacteria by adding normal sodium hydroxide solution (gen- 

 erally 1.5 ml. per liter medium) to Bacto-Levine E.M.B. Agar. This selective 

 medium gave superior results to that obtained with Desoxycholate Citrate Agar, 

 and gave uniformly good results as did S S Agar in the examination of stools. 

 The authors suggest that the selective Levine E.M.B. Agar be supplemented by 

 an enrichment such as Tetrathionate Broth in laboratories doing routine stool 

 examination. 



Levine-E.M.B. Agar inoculated the same day as rehydrated may be used with- 

 out autoclave sterilization. Under these conditions the medium need be heated 

 only to boiling to dissolve it completely before pouring into plates. ' 



To rehydrate the medium, suspend 37.5 grams of Levine E.M.B. Agar in 1000 

 ml. of cold distilled water and 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.). The characteristic flocculant precipitate present in the 

 medium following autoclaving may be evenly dispersed by gently twirling or 

 shaking the flask just prior to pouring into sterile petri dishes. The final reaction 

 of the medium will be pH 7.1. 



One pound of Levine E.M.B. Agar will make 1 2 liters of medium. 



* Standard Methods for the Examination of Water and Sewage, gth Edition: 328:1946. 

 of Water and Sewage, gth Edition: 195:1946. * Bull. 62, Iowa Eng. Exp. Sta., 1921. 



* Standard Methods for the Examination ^ Standard Methods for the Examination 



of Dairy Products, gth Edition: 134:1948. of Water and Sewage, gth Edition: i87:ig46. 



"Standard Methods for the Examination ^Am. J. Clin. Path., 17:561:1947. 



BACTO 



BRILLIANT GREEN BILE 2% (B7) 



DEHYDRATED 



Bacto-Peptone 10 g. 



Bacto-Lactose 10 g. 



Bacto-Oxgall 20 g. 



Bacto-BrilHant Green 0.0133 g. 



Bacto-Brilliant Green Bile 2% is recommended for the confirmation of pre- 

 sumptive tests for members of the coliform group in the bacteriological examina- 

 tion of water according to "Standard Methods for the Examination of Water 

 and Sewage"^ and for the detection of members of the coliform [Escherichia- 

 Aerobacter) group in milk and dairy products as specified in "Standard Methods 

 for the Examination of Dairy Products."^ This medium may also be used in the 

 control of water filtration plant operation as described in Appendix I of "Stand- 

 ard Methods for the Examination of Water and Sewage"^. 



The development of a selective medium which would inhibit organisms other 

 than members of the coliform group has long been of interest to sanitary bac- 

 teriologists. The principal interest has been in media containing bile and brilliant 



