Probiotic Fermented Food Inhibits Viral Infection; a Concept of Modern Era

The utilization of fermented foods has been a longstanding practice in human civilization worldwide for example sauerkraut from the Roman Empire, Jiangshui, and PaoCai, which are popular traditional foods in China. In Korea, Russia, and Mongolia, Kimchi and Kefir are widely used. Similarly, Japan, Indonesia, and Pakistan have their traditional fermented foods such as Miso, Natto, Tempeh, and sourdough, respectively. In America and Europe, fermented alcoholic beverages made from sorghum and maize are among the most common. Nevertheless, the full potential of fermented foods to enhance the bioavailability of bioactive compounds and restore probiotic communities has yet to be thoroughly explored. In this review, we focus on the bioactive compounds and probiotic stability in food fermented with probiotic bacterial strains. Probiotic fermented food improves the bioactive compound contents and has been gaining interest in basic and clinical research. Bioactive compounds, including phenolic, alkaloids, terpenoids, flavonoids, stilbenes, coumarins, tannins, anthocyanidins, flavones, isoflavonoids, and polyphenols, along with beneficial bacteria such as Lactobacilli, Bifidobacteria, Pediococcus, and Weissella demonstrate increased levels and restoration in probiotic fermented foods. These bioactive compounds, combined with a thriving microbiota, play a role in preventing viral infections by targeting influenza, noroviruses (NoVs), Murine norovirus-1 (MNV-1), and COVID-19, while also stimulating the host's immune function. Clinical and pre-clinical investigations are warranted to explore the dose-response and duration efficacy of probiotic fermented foods against viral infections.