Dissolve above ingredients except potassium cyanide and autoclave 15 min at 121°C. Cool and refrigerate at 5-8°C. Final pH, 7.6 ± 0.2.

Prepare KCN stock solution by dissolving 0.5 g KCN in 100 ml sterile distilled water cooled to 5-8°C.

Using bulb pipetter, add 15 ml cold KCN stock solution to 1 liter cold, sterile base.

DO NOT PIPET BY MOUTH!!!
Handle with gloves!!

Mix and aseptically dispense 1.0-1.5 ml portions to 13 x 100 mm sterile tubes. Using aseptic technique, stopper tubes with No. 2 corks impregnated with paraffin. Prepare corks by boiling in paraffin about 5 min. Place corks in tubes so that paraffin does not flow into broth but forms a seal between rim of tubes and cork. Store tubes at 5-8°C no longer than 2 weeks before use.

Hypertext updated by rim/cjm 2005-OCT-21