The Changes of Phenotypic Characteristics of Shewanella putrefaciens under Cold Adaptation

Shewanella putrefaciens (S. putrefaciens) is frequently detected as a serious threat to food safety because it causes spoilage of aquatic products during cold chain transportation. Here, we studied phenotypic changes in S. putrefaciens at low temperatures to discuss the specific behavior of its spoiled aquatic products. S. putrefaciens was found to grow considerably through the growth curve at 0–30°C. In order to investigate the strong putrefaction of aquatic significant amounts under cold storage at 0–10°C, SEM was used to examine the microstructure of S. putrefaciens that had been cultivated at various temperatures. At low temperatures, it was discovered that the cell membrane surface of S. putrefaciens was smoother. FITC-labeled fluorescence microscope was used to view the results. Analysis of S. putrefaciens cultivated at various temperatures revealed that the integrity and permeability of the cell membrane deteriorated with the drop of culture temperature; however, the downward trend slowed down when the temperature was below 10°C. In addition, as the temperature continued to drop below 10°C, the capacity of S. putrefaciens to build biofilms did not diminish noticeably. The findings demonstrate that S. putrefaciens’s cold adaptation mechanism at low temperatures involves modifications to the morphological and phenotypic characteristics of cell membranes, plays a significant role in the organism’s ability to corrode aquatic products at low temperatures, and provides an important target for prevention and control of S. putrefaciens’ ability to contaminate aquatic products and cause financial losses.