1. Suspend 21g of powdered medium in 700mL of puriifed water and mix well. Heat with frequent agitation and boil for 1 minute to completely dissolve the powder. 2. Autoclave at 121°C for 15 minutes. Cool medium to 50-60°C. 3. Aseptically add 300ml of sterile supplement of choice (e.g., mixture containing horse serum and yeast extract) to the medium. Add selective agents (e.g., thallium acetate or penicillin) if desired. 4. Aliquot into appropriate sterile tubes or plates.

Store powdered media at RT. Stable for 12 months after receipt. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.