Effects of C6-HSL and chlorogenic acid on spoilage characteristics of Serratia liquefaciens isolated from mutton

Abstract

Abstract Bacterial quorum sensing (QS) regulates spoilage phenotypes in meat products, but QS-based interventions for mutton preservation remain underexplored. Serratia liquefaciens , a predominant mutton spoilage bacterium, coordinates spoilage through AHL-mediated QS. This study investigated AHL regulation of S. liquefaciens spoilage using exogenous N‑hexanoyl‑L‑homoserine lactone (C6‑HSL) and inhibitor chlorogenic acid, comparing effects via phenotypic and transcriptomic analyses. Exogenous 20 µmol/mL C6-HSL significantly enhanced N‑acyl homoserine lactone (AHL) activity (1.26-fold), biofilm formation (51.55%), protease activity (37%), and siderophore production (26.78%). Conversely, 80 µg/mL chlorogenic acid markedly inhibited AHL activity (26.19%), biofilm formation (42.54%), protease activity (28.92%), and motility (38.34%). In mutton storage trials, chlorogenic acid significantly reduced total viable counts and delayed the increase in pH during the first 9 days of refrigerated vacuum storage, effectively retarding microbial spoilage and maintaining meat quality. Transcriptomic analysis revealed differential regulation: C6-HSL up-regulated genes involved in flagellar assembly ( fliJ , cheW ), adhesion ( fimA ), and iron acquisition ( iucD ); chlorogenic acid down-regulated adhesion ( fimA ), protein synthesis ( tuf ), stress response ( ibpA ), and nutrient transport ( metQ ). These results suggest that AHL signaling is closely associated with the spoilage potential of S. liquefaciens , and chlorogenic acid acts as a dual-functional QS inhibitor. The present findings provide a molecular reference for exploring mutton preservation strategies based on QS interference.