Fundamental Research on Japanese Fish Sauce and Nuoc Mam

This review compares traditional fish sauces of Japan and Vietnam, highlighting their cultural roles, production methods, and microbial characteristics. While fish sauce is widely linked with Southeast Asia, Japan has long produced fermented seafood condiments such as shottsuru, ishiru, and squid-based sauces from Tobishima Island. These Japanese products, though rich in tradition, are becoming rare due to aging populations and shifting dietary habits. We focus on Tobishima's squid-based sauce, still handmade in some households. Despite using similar ingredients, samples showed distinct flavors. Metabolomic and metagenomic analyses revealed differences in amino acid content and microbial composition, shaped by each family's unique techniques. In contrast, Vietnamese nước mắm, especially from Phú Quốc, Phan Thiết, and Nam Ô, remains central to national cuisine and export markets. Made from anchovies and salt, it ferments over months to years in wooden barrels, developing a strong umami flavor. Microbial communities dominated by halophilic bacteria and yeasts drive this transformation, with regional practices influencing quality. This review highlights the diversity and depth of fish sauce traditions in both countries. Preserving artisanal knowledge and promoting cross-cultural appreciation are essential for sustaining these culinary heritages in the face of industrialization and globalization.