Fermented Soybean Foods: Significance of Biogenic Amines

Microbial fermentation of soybean leads to the formation of biogenic amines that may cause intoxication symptoms in human. However, the safety issues of fermented soybean foods have been overlooked because human ancestors have taken these foods for centuries. Even though fermented soybean foods are believed to have health-promoting and -protective effects, it is important to monitor and reduce biogenic amine levels in the fermented foods because they contain not only abundant dietary amino acid precursors of biogenic amines, but also various biogenic amine-producing microorganisms. According to reports on biogenic amines, the amounts of biogenic amines in most fermented soybean foods are within the safe levels for human consumption. However, several types or samples of these fermented foods have the contents of vasoactive biogenic amines greater than a toxic dose of each amine. Therefore, it is also important to understand why there are differences in the contents and diversity of biogenic amines between types or batches of fermented soybean foods. Meanwhile, several biocontrol strategies have been developed for reducing biogenic amine formation in fermented foods, mainly focusing on microbial intervention, i.e., the use of starter and protective cultures that have the ability to degrade biogenic amines and inability to produce biogenic amines. However, little attention has been given to both starter and protective cultures for fermented soybean foods. In addition, when screening starter and protective cultures, genetically designed cultures needs to be considered to ensure the safety of fermented foods in the future.