The Role of as a Key Producer and Fermentation Condition as an Influencing Factor in Tyramine Accumulation in .

The study evaluated the role of in tyramine production and its response to fermentation temperature in a traditional Korean fermented soybean paste, . Tyramine content was detected in retail products at high concentrations exceeding the recommended limit up to a factor of 14. All retail products contained spp. at concentrations of at least 6 Log CFU/g. Upon isolation of strains, approximately 93% (157 strains) produced tyramine at over 100 µg/mL. The strains that produced the highest concentrations of tyramine (301.14-315.29 μg/mL) were identified as . through 16S rRNA sequencing. The results indicate that is one of the major contributing factors to high tyramine content in . During fermentation, tyramine content in groups co-inoculated with strains was highest at 45 °C, followed by 37 °C and 25 °C. The tyramine content of most groups continually increased as fermentation progressed, except groups fermented at 25 °C. At 45 °C, the tyramine content occasionally exceeded the recommended limit within 3 days of fermentation. The results suggest that lowering fermentation temperature and shortening duration may reduce the tyramine content of , thereby reducing the safety risks that may arise when consuming food with high tyramine concentrations.