Production Process

  • Tane-koji(seed koji) is produced by culturing koji mold on rice until the spores become sufficiently epiphytic. In order to do so, the rice must be processed so that the koji mold can grow easily and for a long time. This processing step is called the raw material processing stage. The raw material processing stage onsists of six operations.

    Immersion tank 850 kg of rice are soaked in two tanks.Immersion tank
    850 kg of rice are soaked in two tanks.

    Steaming vat The rice is then drained, steamed, cooled, inoculated with koji mold and initially cultured in this steaming vat.Steaming vat
    The rice is then drained, steamed, cooled, inoculated with koji mold and initially cultured in this steaming vat.

    • 1. Rice polishing

      Brown rice is polished to roughen the outer surface of the rice. (rice-polishing ratio is 97-98%) Most of the surface of the brown rice is left on since it contains many nutrients that help the koji mold grow.

    • 2. Washing

      The rice is thoroughly washed to remove any chaff or dust. If any chaff remains, it may cause bacterial contamination.

    • 3. Soaking

      For good growth of koji mold, the rice must absorb a sufficient amount of water. Characteristics of each lot of supplied rice slightly vary, even for the same variety from the same production area. Consequently, soaking time is determined by thoroughly testing the characteristics of the supplied rice.

    • 4. Draining

      After the rice has absorbed a sufficient amount of water, it is removed from the water for a while so the moisture between rice grains can evaporate. If water remains in between the grains, this will cause the rice to stick together when steamed.

    • 5. Steaming

      After the rice is soaked and drained, it is steamed to convert the starch and the protein into a form that the koji mold can easily digest. In order to always obtain the same, uniform results, fine adjustments such as adjusting the steaming time depending on each lot of rice are required. Most microorganisms die during the steaming process, but in Bio’c, high pressure is applied at the end of the steaming process to sterilize any remaining bacteria.

    • 6. Cooling

      The steamed rice is then cooled to the right temperature for koji mold to grow, in aseptic air which has been passed through a HEPA filter.