The medium prepared as above is poured into the desired culture vessels (15 ml for 25 x 150 mm culture tubes; 50ml for 150 ml flasks) which are plugged with non – absorbent cotton wool wrapped in cheese cloth. The vessels are transferred to baskets and covered with aluminium foil and sterilized by autoclaving at 120°C for 15 min. If plastic culture vials (unautoclavable) are used, the medium is autoclaved in 250 or 500 ml flasks before it is poured into the vials. In this case, medium is allowed to cool to 60°C before pouring. In either case culture vessels may be stored at 4°C and used whenever needed