Early microbial succession and matrix destabilization guide long-term preservation of refrigerated kelp

Traditional monitoring of fresh kelp spoilage relies on terminal chemical indicators like total volatile basic nitrogen (TVB-N), inherently obscuring the early interplay between microbial succession and matrix physical degradation. Here, using a stage-resolved analytical framework, we synchronized microbial and physicochemical data to reveal that kelp deterioration is characterized by an early ecological trajectory shift that precedes conventional chemical spoilage signals. We observed a rapid microbial transition marked by severe community simplification and Pseudomonas dominance. Notably, this shift preceded TVB-N accumulation by approximately five days and coincided with tissue softening and pronounced changes in water mobility. Guided by these stage-resolved observations, we developed a pH-salt-moisture hurdle strategy for long-term preservation. The treatment successfully maintained spoilage control for six months and prevented Pseudomonas dominance. These findings support early microbial trajectory control as a practical framework for spoilage assessment and preservation of refrigerated kelp.