• Casein hydrolysate 6.00 g
• K₂HPO₄ 0.20 g
• MgSO₄.7H₂O 0.20 g
• FeSO₄.7H₂O 2.00 mg
• Glycerol 2.00 ml
• L-Asparagine 0.15 g
• Vitamin B₁₂ (see below) 10.00 ml
• Agar powder 15.00 g
• Distilled water 1.0 L

Dissolve the ingredients in 700 ml distilled water with gentle heating in the order given above. Use a few drops of HCl to dissolve the asparagine and adjust pH to 7.0. Filter. Add glycerol and agar. Steam to disolve, distribute and sterilize in autoclave at 121 °C for 15 min. Allow to set in a slanted position.

Vitamin B₁₂ (cyanocobalamin) solution

• Vitamin B₁₂ 0.4 mg
• Distilled water 10 ml