MAINTENANCE AND PRESERVATION OF CULTURES 115 



33. Tomato-juice Agar 



Tryptone 10 g 



Yeast extract 10 g 



Agar 12 g 



Distilled water 800 ml 



Heat to 100°C; adjust pH to 7.2; add 



Tomato juice 250 ml 



Tube for stabs; autoclave. The tomato juice must be taken from canned unsea- 

 soned tomatoes, not from commercial juice 'preparations. It is prepared by filtering 

 the juice from a No. 2 can, keeping refrigerated overnight, then adjusting pH to 7.0. 



34. Tomato, Yeast, Milk Medium 



Dehydrated skim milk 100 g 



Yeast extract 5 g 



Distilled water 1,000 ml 



Mix well and add 



Tomato juice, pH 7.0, as in formula 33 100 ml 



Methylene blue 1.5% solution in alcoholic KOH 2 ml 



Filter through cheesecloth, tube, and autoclave. 



35. Tryptone Glucose Yeast Agar 



(Northern Regional Research Laboratory) 



Tryptone 5 g 



Yeast extract 5 g 



Glucose 1 g 



K2HPO4 1 g- 



Agar 20 g 



Tap water 1,000 ml 



pH 7.0 



36. Urea Agar 



Urea 10 g 



Distilled water 100 ml 



Sterilize by filtration. Add ig ml per tube aseptically to nutrient agar (No. 23) 

 after melting and cooling to 45-50°C. Mix well; cool for slants. 



37. V-8 Juice Agar 



V-8 juice (Campbell Soup Co.) 200 ml 



CaC03 3g 



Agar 15 g 



Tap water 800 ml 



pH7.2 



The V-8 juice can be filtered or not depending on the clarity desired, and the amount 

 of CaCOs may be varied to give a different pH. 



