INTRODUCTION
Thua nao is a Thai traditional non-salted
product fermented by Bacillus spp. It is produced
in the northern Thailand and utilized as a substituent
for fish paste (Sundhagul et al., 1972). To make
traditional Thua nao, soybeans are washed, soaked
overnight, cooked thoroughly until soft, drained
and fermented naturally without inoculation and
leave on banana leaf lined baskets for 3 or 4 days
until surface of the beans are covered with a sticky,
viscous, colorless gum and are accompanied by a