The Road to Sustainable Soy Sauce Production and Consumption

Soy sauce (SS), a fermented condiment integral to various global cuisines, has undergone considerable technological advancements while preserving its traditional microbiological processes. This systematic review, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, synthesized findings from 181 peer-reviewed articles to examine trends in SS production and consumption. Our descriptive statistics and thematic analysis revealed five key focus areas: process optimization, microbial fermentation, safety, waste management, and evolving analytical technologies. Advances, such as metagenomics, synthetic biology, and enzyme engineering, have refined fermentation dynamics, improving flavor and production efficiency. Concurrently, sustainability-orientated innovations, including by-product bioconversion, low-sodium formulations, and traceable packaging, support both environmental goals and health-conscious consumption. The integration of multi-omics approaches (e.g., metabolomics, genomics, and transcriptomics) and high-resolution analytical tools (e.g., spectroscopy and sensor-based systems) has further strengthened quality control by enhancing authenticity, safety, and traceability. However, integrating traditional methods with emerging technologies such as precision fermentation, which facilitates targeted microbial control to improve product consistency, remains challenging due to microbial strain incompatibility, scalability issues, and the necessity to maintain cultural authenticity and sensory attributes. It is essential to implement scalable and sustainable solutions that improve microbial function while minimizing hazardous by-products and environmental effects. This review presents an integrated framework connecting five key thematic areas with the core pillars of sustainability: environment, economy, society, technology, and nutrition, offering a foundation for directing future research, policymaking, and industrial practices. Key priorities include the development of salt-tolerant microbial consortia, the valorization of fermentation by-products via circular economy strategies, and the standardization of sustainability certification criteria to facilitate practical implementation.