Monascus spp. is a filamentous fungus that can produce beneficial secondary metabolites including Monascus pigments (MPs), monacolin K and γ-aminobutyric acid (GABA), which possess the important biological activities such as acting as a colorant, anti-cancer and anti-inflammation agent. Therefore, Monascus is widely used in such industries such as foods, medicine and brewing. However, Monascus can produce citrinin with nephrotoxicity, which limits its application. In this review, we systematically summarize the latest research progress on the synthesis pathway, biological activity and synthesis regulation of MPs, monacolin K, GABA and citrinin, as well as the application of Monascus in dairy products. We hope that this review can provide new ideas for the safe development of dairy products fermented by Monascus.

A lactic acid bacteria (LAB) strain BD-1 was isolated from red fermented bean curd, and the effect of BD-1 and its fermentation supernatant on the production of Monascus pigments (MPs) by Monascus purpureus ATCC 16365 was studied. The results showed that BD-1 was identified as Lactobacillus plantarum through Gram staining, physiological and biochemical profiles and 16S rRNA gene sequencing. Five different inoculum sizes of 0.2%, 0.4%, 0.6%, 0.8% and 1.0% were tested for strain BD-1 and ATCC 16365 was cultured for 0, 24 or 48 h. It was found that adding 0.6% BD-1 to the fermented medium with ATCC 16365 after culture for 24 h markedly increased the color value and synthesis of extracellular Monascus pigments (EMPs) and intracellular Monascus pigments (IMPs). Under this condition, the color values of EMPs and IMPs were (6.24 ± 0.05) and (288.14 ± 6.82) U/mL, and their synthesis was increased by (146.55 ± 7.84)% and (16.07 ± 0.30)% compared with the control group, respectively. In addition, adding the fermentation supernatant of BD-1 to ATCC 16365 also remarkably increased the color value and synthesis of EMPs, which were increased to 4.20 U/mL and by (29.85 ± 5.40) % compared to the control group, respectively. In summary, the optimal inoculum size of BD-1 for MPs production was 0.6%.