Abstract: The electroactive bacterium Shewanella is a dominant spoilage microorganism in food products such as cold chain aquatic products. Its extracellular electron transfer (EET) mechanism is not only a core physiological characteristic, but also the key link between molecular metabolism and food spoilage phenotypes. In this article, we summarize the direct and indirect electron transfer pathways of EET in Shewanella, and clarify the localization and functions of the core components in each pathway. Furthermore, the regulatory mechanism of the EET pathway is explained, and the internal relationship between EET and spoilage is analyzed. The regulation of the EET efficiency and spoilage ability by low temperature, acid stress and high salt is systematically elucidated. This review clarifies the complete pathway of Shewanella EET from molecular regulation to spoilage phenotypes, providing theoretical support and technical ideas for targeted blocking of the EET pathway and for promoting the translation of basic research on cold chain food preservation into practical applications.

Key words: Shewanella; extracellular electron transfer; regulatory pathway; spoilage ability