standard nutrient agar (SNA):
1 g l−" KH#PO%, 1 g l−" KNO$, 0±5 g l−" MgSO%¬7 H#O,
0±5 g l−" KCl, 0±5 g l−" glucose¬H#O, 0±2 g l−" sucrose,
20 g l−" agar and medium VIII : starch yeast extract agar
(SYA): 15 g l−" soluble starch, 4 g l−" yeast extract, 800 ml l−