Nutrient Agar 1.5% is the modification of Nutrient Agar recommended by APHA for cultivation and maintenance of nonfastidious microorganisms (1). This medium is used as a general- purpose medium. Recently ISO Committee (2) has also recommended it with slight modification for subcultivation of Pseudomonas species isolated from meat and meat products.
Peptic digest of animal tissue is the principal source of organic nitrogen while beef extract provides carbohydrates, vitamins, organic nitrogen compounds and salts. Nutrient Agar 1.5% may be used for blood culturing work after the addition of sterile 5-10% v/v defibrinated blood. Sodium chloride makes the medium isotonic preventing haemolysis of red blood corpuscles.
Directions: Suspend 31 grams in 1000 ml distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. If desired, it can be appropriately enriched with sterile blood, ascetic fluid or serum after cooling to 45-50°C. Mix well and dispense as desired.