[P004] Poster

1:00 PM - 1:50 PM JST(4:00 AM - 4:50 AM UTC)

[P02-164] Evaluation of the Effect of Mixed Starter Cultures on the Control of Mycotoxins in Meju

○HYUNWOOK JANG¹ (1. Rural Development Administration (Korea))

Keywords:

traditionally fermented soybean products,MEJU,Mixed Starter,Aspergillus oryzae,Bacillus subtilis

With increasing variability in environmental conditions, particularly under elevated temperature regimes, the control of fermentation processes in traditionally fermented soybean products has gained growing attention. In this context, the use of defined starter cultures has been proposed as an effective strategy to modulate microbial dynamics and improve the consistency of fermentation outcomes. In particular, selected microorganisms may contribute to the regulation of undesirable metabolites, including mycotoxins and biogenic amines, during fermentation. Therefore, this study aimed to evaluate the effect of mixed starter cultures on the control of mycotoxin production and quality characteristics during meju fermentation. After boiling and cooling soybeans, Aspergillus oryzae P4 (0.3%) and Bacillus subtilis DYJ24 (0.1%) were inoculated, mixed thoroughly, and shaped into meju blocks. Fermentation was conducted at 30°C, and physicochemical properties (moisture content, pH, total acidity, amino-nitrogen, and reducing sugars), microbial populations (molds, lactic acid bacteria, and Bacillus spp.), and hazardous compounds (aflatoxin, ochratoxin, and biogenic amines) were analyzed over a 0–30 day fermentation period. Results showed that moisture content decreased and total acidity increased from 0.25% at day 0 to 2.83% at day 30 in both control and starter-treated groups. Amino-nitrogen, a key quality indicator of meju, was significantly higher in the starter-treated group (227 mg%) compared to the control (110 mg%) at day 20, indicating increased protein hydrolysis. Reducing sugars also increased, showing 2.43% in the starter-treated group and 1% in the control at day 0, and 3.86% and 1.57% at day 30, respectively. Microbial analysis revealed higher initial microbial counts in the starter-treated group, confirming successful inoculation. Regarding hazardous compounds, aflatoxin levels were reduced by approximately 57%, from 3.67 μg/kg in the control to 1.58 μg/kg in the starter-treated group. Ochratoxin was detected at 171.62 μg/kg in the control but was not detected in the starter-treated group. In conclusion, the use of selected starter cultures capable of reducing mycotoxin production not only enhances flavor-related components such as amino-nitrogen but also improves safety by effectively lowering mycotoxin levels in meju.