NaCl-Added Soybean Fermentation and Post-Fermentation Moisture Modulation: Effects on Safety and Shelf Life of a Traditional, Nonsalted Alkaline Food

The present study aimed to evaluate the effect of adding NaCl prior to fermentation and moisture reduction after the fermentation on the safety and shelf life of kinema, a Bacillus-fermented soybean food. The physicochemical parameters of kinema decreased with an increase in the concentration of NaCl up to 4 g/100 g where there was no significant change in cell count of the fermenting microorganism (Bacillus subtilis) and sensory score of the product but eliminated Bacillus cereus. Escherichia coli was reduced by 1 log cycle in the presence of NaCl but eliminated when the water activity (aw) of kinema was reduced to 0.5 after fermentation. Salt had no effect on its shelf-life. Storage stability was determined in terms of its moisture sorption isotherms. Thermodynamic functions decreased with increasing moisture content. The monolayer moisture content ranged from 6.0 to 8.3 g/100 g and the optimum aw for storage of kinema was =0.5.