Antibiotic Assay Medium No. 4 (Yeast Beef Agar)

Peptic digest of animal tissue
(peptone) 6.000 G/L
Beef extract 1.500 G/L
Yeast extract 3.000 G/L
Dextrose 1.000 G/L
Agar 15.000 G/L
pH range 6.40 - 6.80
Reaction reaction of 2.65% w/v aqueous
solution at 25°C pH: 6.6 ñ 0.2