Research highlights in bacteriophages of fermented soybean foods

Since their discovery, bacteriophages - viruses that infect bacteria - have fascinated scientists due to their ubiquity and potential applications in fields ranging from molecular biology to biotechnology and medicine. However, in fermentation processes that depend on bacterial activity, bacteriophages can pose a major threat by infecting and disrupting key microbial populations, leading to delayed or failed fermentations and resulting in economic losses. While the impact of bacteriophages on fermented dairy foods, such as yogurt and cheese, is well-documented, such knowledge is comparatively limited for fermented soybean foods (FSFs). Most FSFs (such as Cheonggukjang, Miso, Thua Nao, and soy sauce) are traditionally produced using natural microbiota under less controlled conditions. This makes them more susceptible to unpredictable microbial dynamics, including phage interference. In this review, we examine the diversity and occurrence of bacteriophages associated with FSFs. Finally, the potential roles of bacteriophages in FSFs - ranging from fermentation disruption to possible microbial modulation - are also discussed.