2007 Volume 54 Issue 12 Pages 528-538
To obtain strains of bacteria suitable for the production of natto that we have not yet been able to collect in Japan, we explored the Northeastern region of Myanmar. We obtained twenty-nine Pe pok samples with saline concentrations between 0.14% and 13.7%. We isolated 197 bacteria from the samples and identified 137 strains of Bacillus subtilis. We selected 42 of these strains as natto bacilli, as judged from the stickiness of colonies grown on steamed soybeans. The optimal growth temperatures of those 42 strains were as follows : 33°C, 1 strain ; 35°C, 1 ; 37°C, 5 ; 39°C, 9 ; 41°C, 19 ; 43°C, 6 ; 45°C, 1. After manufacturing itohiki-natto by programming the temperature and moisture throughout the manufacturing process, 10 natto bacilli with high scores in sensory tests were selected. Six strains produced natto very similar to Japanese natto, but with a softer texture. The remaining strains produced natto with a distinctive flavor, taste, or texture from those of typical Japanese itohiki-natto. These results showed that certain selected natto bacilli could produce natto characteristics never before seen in Japan.
