Milk Lipids as Bioactive Modulators of the Bacterial Proteome: Mechanisms Linking Dairy Management to Microbial Performance.

Milk lipids are critical determinants of dairy product quality, human health, and animal welfare. Their composition is shaped by a complex interplay of genetic, dietary, physiological, and environmental factors. These lipids play a pivotal role in modulating the expression and function of bacterial proteins in both indigenous microbiota and starter cultures. However, the mechanistic pathways linking farm-level factors to the microbial phenotypes observed during dairy fermentation remain underexplored. This review synthesizes existing knowledge on how intrinsic and extrinsic factors modify milk production and lipid profiles in dairy animals and indirectly reshape bacterial protein expression. By using a cross-species approach comparing milk lipid metabolism in dairy animals and humans, we bridge critical knowledge gaps to inform future optimization strategies. We examine evidence linking lipid profiles to microbial protein synthesis and localization, with a special focus on the adaptive role of moonlighting proteins. Finally, this review proposes a novel integrative framework linking livestock management practices directly to microbial performance in dairy fermentation. This perspective identifies milk lipids not merely as nutrients, but as bioactive modulators of the bacterial proteome, offering a new paradigm for enhancing dairy safety and functionality.