Monascus purpureus (Red koji mold)
Monascus purpureus
Japanese: 紅麹菌（Monascus purpureus）
A type of koji mold that produces red pigments. Used in Okinawan tofu-yo, Chinese red rice wine, and red fermented tofu. Some strains produce citrinin, requiring careful strain selection.
Red koji mold produces vivid red pigments. Red koji, made by growing this mold on rice, has been used for food coloring and fermentation across East Asia since ancient times. Okinawan tofu-yo, Chinese red rice wine, and red fermented tofu are representative examples.
Monacolin K, a compound produced by this mold, is known to lower cholesterol levels. However, some strains also produce citrinin, a harmful substance, making safety verification of strains essential.
Behind its beautiful colors lies both usefulness and risk. Red koji mold symbolizes the complexity of fermentation microorganisms. Knowing the microbial world connects to understanding fermentation.