Dehydroacetic acid disrupts cold adaptation and biofilm formation in Pseudomonas lundensis: A targeted strategy for enhancing microbiological safety of refrigerated poultry.

Refrigerated roast chicken exhibits limited shelf stability (5-7 d) despite modified atmosphere or vacuum packaging, primarily due to Pseudomonas lundensis, a psychrotrophic specific spoilage organism. This pathogen's persistence depends on cold-shock protein A (CspA)-mediated cryoprotection and AlgK/RpoS-dependent biofilm formation, enabling proteolytic and lipolytic activities even under hurdle technologies. Herein, we report dehydroacetic acid (DHA) as a targeted low-temperature adaptation inhibitor (LATI) against this spoilage mechanism. Virtual screening of traditional Chinese medicine and food-grade compound libraries identified DHA, which at sub-inhibitory concentrations selectively attenuated P. lundensis growth at 4 °C versus 28 °C. Scanning electron microscopy showed that after adding DHA, the extracellular polymers of P. luendsis significantly decreased, and the content of alginate decreased by 23.1% and impaired biofilm architecture with compromised membrane integrity. In refrigerated chicken, DHA retarded pH elevation, thiobarbituric acid reactive substances and total volatile basic nitrogen accumulation, while suppressing total viable counts and off-odor development. Multi-omics analyses demonstrated DHA-mediated downregulation of CspA, disruption of ATP-binding cassette (ABC) transporters, and perturbation of 2-oxocarboxylic acid metabolism-collectively arresting bacterial proliferation under cold stress. RT-qPCR confirmed 9.77-fold transcriptional suppression of cspA. This study establishes DHA as a novel LATI agent that selectively targets psychrotrophic machinery, offering a mechanistically grounded strategy for precision preservation of refrigerated poultry.