Abstract BACKGROUND Industrial processing of lactic acid bacteria (LAB) frequently exposes cells to acute low‐temperature stress during frozen handling, cold‐chain transport, and pre‐lyophilization stabilization. These short‐term freezing events disrupt membrane integrity and reduce the viability of LAB, including Lactiplantibacillus plantarum , compromising product quality and functional performance. This study evaluated whether activating the endogenous quorum sensing pathway could enhance biofilm development and improve tolerance to acute freezing stress (−20 °C, 2 days) in L. plantarum JB1. RESULTS Compared with the wild type, the activity of the signaling molecule AI‐2 in the dual‐plasmid strain increased by 2.31‐ to 3.40‐fold from 4 to 24 h, peaking at 8 h, while the expression level of the luxS gene increased by 50.83‐fold. Biofilm formation reached its peak at 24 h, maximum biofilm formation increased by 2.47‐fold relative to the wild type, and the expression level of the luxS gene increased by 27.64‐fold compared with the wild type. Hydrophobicity increased 1.88‐fold, from 38.6% (wild type) to 72.4%. After freezing, the viable cell counts of the dual‐plasmid strain increased by 15.02‐fold compared to the wild type. Live/dead fluorescence staining further confirmed enhanced cryotolerance, with the quorum sensing (QS)‐activated strain exhibiting a higher live cell proportion and reduced membrane‐damaged cells relative to the wild type across all sampling points, with the live/dead ratio increasing 1.95‐ to 10.67‐fold. CONCLUSION Activation of the LuxS/AI‐2 QS pathway increased AI‐2 activity, surface hydrophobicity, and biofilm biomass in L. plantarum JB1. These enhancements translated into improved tolerance to acute freezing, with higher viable counts and superior membrane integrity. © 2026 Society of Chemical Industry.
Sun et al. (Sat,) studied this question.