In traditional soy sauce, aspergilli, film and pellicle-forming yeasts may cause spoilage. The principal contaminants of koji are coagulase-negative Staphylococcus spp. and B. subtilis. As well as a salt-tolerant wild yeast Z. rouxii var. halomembranis can grow in moromi. Additionally, oxidation over time can result in deterioration of the soy sauce aroma and flavor.
Addition of EpolylyTM for inhibiting coagulase-negative and yeasts,and Bamboolex® for anti-oxidation are necessary to extend the shelf life soy sauce.