Abstract: [Objective] To explore the effect of different solid-state fermentation techniques of lactic acid bacteria （LAB） on the bioavailability of active components of Astragalus membranaceus （AM） and evaluate its safety. [Methods] AM powder was fermented anaerobically using seven LAB strains （ZW0410,FJ0021,LYS0032,BJLY0086,SS0204,WT0327,GL0108） under raw material conditions （substrate∶water=1∶0.5, 2% inoculum, 37 ℃ for 48 h）. Parameters including pH, microbial activity （LAB count）, lactic acid content and functional components （total flavonoids, crude polysaccharides, total sugars） were measured to screen optimal LAB strains. [Results] Six LAB strains （ZW0410, FJ0021, LYS0032, BJLY0086, SS0204, WT0327） could ferment AM. After fermentation, the number of LAB could reach more than 10⁸ CFU/g, and the lactic acid content was significantly （P<0.05） higher than that of the control group. The ZW0410 group showed the best effect. The number of LAB reached 2.64×10⁹ CFU/g, lactic acid content was 14.84 g/kg, pH decreased to 4.12, total flavonoids and crude polysaccharides increased to 18.06 g/kg （1.65 times higher than the blank group） and 36.93 g/kg, respectively, and total sugar content decreased by 6.4 percentage points. The Lactic acid bacteria BJLY0086 group showed the highest total flavonoid content（19.48 g/kg, 1.86 times higher than the blank group）. In addition, LAB fermentation significantly inhibited mold proliferation （No mold was detected except GL0108 group）, while mycotoxins aflatoxin B₁ （AFB₁）, zearalenone （ZEN）, deoxynivalenol （DON） and Escherichia coli remained within safe limits. [Conclusion] Under the conditions of this experiment, Lactobacillus plantarum ZW0410 was identified as the optimal strain for AM fermentation. Using this lactic acid bacterium to ferment AM, the content of total flavonoids and crude polysaccharides could be significantly （P<0.05） improved, and the growth of mold could be inhibited.

Key words: Astragalus membranaceus, lactic acid bacteria, fermentation, active components