Challenges and perspectives for engineering studies on traditional food solid-state fermentation: insights from Baijiu production

Traditional spontaneous solid-state fermentations are widely used to produce foods and beverages such as cheese in the West and Baijiu in the East, and represent heritage-driven processes that continue to play a vital role in regional culture and food industry. As a representative example, Baijiu’s annual production exceeded 4 million kiloliters (50%, ABV) with sales surpassing USD 110 billion (approximately 10% of the entire food industry output in China, 2024). Despite the culture and commercial importance, the fermentation process operates as highly complex multi-species and multi-physics solid-state systems and is still largely managed through empirical control and partial mechanization, posing major challenges for monitoring, process control, standardization, and industrial scale-up within conventional process engineering frameworks. Using Baijiu production as a representative case study, we summarize successful approaches and drawbacks in relevant studies on engineering principles. We examine the engineering challenges of traditional solid-state fermentation, highlighting the limitations of current studies in achieving process standardization and optimization. We addressed engineering-oriented strategies including sensor development, process modeling, down-scaling methods, and AI-assisted digital twin frameworks. We proposed rational design of whole process to enhance reproducibility, efficiency, and scalability. This perspective demonstrates that precision engineering of traditional solid-state fermentation is now feasible, offering pathways to modernize these processes while preserving their characteristic qualities.