Study on red fermented rice with high concentration of monacolin K and low concentration of citrinin

Red fermented rice (RFR), known as Asian traditional fermentation foodstuff, is now used as natural colorants and a dietary supplement all over the world. However, the discovery of citrinin in RFR has led to a controversy about the safety of RFR. In this paper, a mutant strain, Monascus spp. M12-69, was acquired by treatment with mutagenic agents from a wild strain M12 of Monascus screened from RFR samples gathered around China. According to the classification guide of Hawksworth and Pitt on Monascus genus, they belong to Monascus pilosus Sato. The conditions of solid state fermentation of M12-69 were optimized. At the optimum conditions, the concentrations of monacolin K and citrinin in RFR, which was dried at 50 °C to a constant weight, were 2.52 mg/g and 0.13 ng/g, respectively. These results reveal that Strain M12-69 is a potential strain, which can be used to produce RFR with high concentration of monacolin K and low concentration of citrinin.