Debaryomyces hansenii ST14 exhibiting antagonistic activity against Pseudomonas lundensis improves microbial stability and quality of reduced-salt air-dried cured meat.

Reducing sodium chloride in air-dried cured meat weakens microbial stability and accelerates quality deterioration. This study evaluated the potential of Debaryomyces hansenii ST14 as a bioprotective culture to improve the microbial stability and quality of reduced-salt air-dried cured meat. In the meat system, D. hansenii ST14 inoculation significantly reduced lipid oxidation and protein degradation, decreasing thiobarbituric acid reactive substances (TBARS) and total volatile basic nitrogen (TVB-N) levels by approximately 52.63% and 35.60%, respectively, compared with the control group, while maintaining physicochemical properties and promoting a more favorable volatile profile, thereby improving overall product stability. In vitro experiments further demonstrated that D. hansenii ST14 exhibited antagonistic activity against Pseudomonas lundensis M, resulting in reduced bacterial growth and biofilm formation under both contact and non-contact conditions. In the reduced-salt meat model, D. hansenii ST14 reduced P. lundensis M populations from 5.37 × 109 to 2.80 × 108 CFU/g, corresponding to a 94.78% inhibition rate. No detectable extracellular antimicrobial activity was observed under the tested conditions, whereas nutrient supplementation partially restored bacterial growth. Carbon source utilization analysis revealed substantial niche overlap between the two microorganisms, with a niche overlap index of 0.667. Transcriptomic and physiological analyses showed that co-culture induced metabolic reprogramming in P. lundensis M. This metabolic response was characterized by enhanced central metabolism and respiratory activity, as well as reactive oxygen species (ROS) accumulation, adenosine triphosphate (ATP) depletion, cell-envelope damage, and impaired biofilm formation. These findings support a nutrient-competition-based mechanism underlying the antagonistic interaction between D. hansenii ST14 and P. lundensis M. D. hansenii ST14 shows promise as a bioprotective culture for improving microbial stability while maintaining product quality in reduced-salt meat products.