To evaluate the safety of Cheonggukjang, 60 different samples collected from 8 provinces all across the country were analyzed for biogenic amine contents by HPLC. The aromatic vasoactive amine (β-phenylethylamine and tyramine) contents in some Cheonggukjang samples exceeded safe levels for consumption. Bacterial and enterococcal counts of Cheonggukjang samples were 9.70 ± 0.43 and 6.00 ± 1.52 Log CFU/g, respectively, and strains of Bacillus (n = 433) and Enterococcus (n = 55) isolated from Cheonggukjang samples were tested for biogenic amine production in assay media. Histamine and putrefactive amines (putrescine and cadaverine) were detected more abundantly in cultures of Bacillus strains, while tyramine was detected in larger quantities in cultures of Enterococcus strains. Subsequently, strains selected based on their specific abilities to produce the aforementioned respective biogenic amines were applied to soybeans to undergo fermentation, and biogenic amine contents in the soybeans were measured during the fermentation period. Unexpectedly, Bacillus strains produced slightly lower levels of histamine, but significantly higher levels of β-phenylethylamine and tyramine than Enterococcus strains. Altogether, this study suggests that Bacillus species are as significant as Enterococcus species for biogenic amine production in Cheonggukjang, including tyramine, and should be controlled accordingly for the reduction of biogenic amine contents in the food.

为了评估青口江的安全性，通过HPLC对从全国8个省份收集的60种不同样品进行了生物胺含量的分析。在一些Cheonggukjang样品中，芳香族血管活性胺（β-苯乙胺和酪胺）的含量超过了安全食用水平。清谷酱样品的细菌计数和肠球菌计数分别为9.70±0.43和6.00±1.52 Log CFU / g，并测试了从清谷酱样品中分离的芽孢杆菌（n = 433）和肠球菌（n = 55）菌株的生物胺生成量媒体。组胺和腐胺（腐胺和尸胺）在大肠杆菌的培养中含量较高。芽孢杆菌属菌株，而在肠球菌菌株的培养物中大量检出了酪胺。随后，将基于其产生上述各个生物胺的特定能力选择的菌株应用于大豆进行发酵，并在发酵期间测量大豆中生物胺的含量。出乎意料的是，与肠球菌菌株相比，芽孢杆菌属菌株产生的组胺水平略低，但β-苯乙胺和酪胺水平显着较高。总的来说，这项研究表明芽孢杆菌属物种与肠球菌物种在清国江的生物胺生产一样重要。，包括酪胺，应相应控制以减少食品中生物胺的含量。