Food products are heterogeneous environments in which pathogenic bacteria can exist as individual cells, surface-associated biofilms, or embedded microcolonies. This spatial organization, which remains largely overlooked in predictive microbiology, may profoundly influence bacterial phenotypes. This thesis investigates the impact of spatially structured growth on the adaptation of foodborne pathogens to food-related stresses and to conditions encountered in the gastrointestinal tract. Using a semi-solid hydrogel model, the responses of planktonic populations and embedded microcolonies were compared. The results demonstrate that spatial structuring modulates bacterial growth in a manner that depends on the species, the type of stress, and its intensity. Under high osmotic stress, several pathogens exhibited enhanced tolerance when growing within the hydrogel matrix. Spatially structured pre-growth also increased tolerance to in vitro stresses mimicking gastrointestinal conditions. This protective effect was further confirmed in vivo using a larval Hermetia illucens infection model challenged with Salmonella enterica serovar Typhimurium. In S. Typhimurium, the integration of transcriptomic, metabolomic, and lipidomic datasets revealed that spatial growth is associated with extensive physiological reprogramming affecting metabolism, stress response functions, and membrane composition. Lipidomic analyses further demonstrated that spatially structured and planktonic populations possess distinct membrane lipid profiles and exhibit different responses to osmotic stress, with microcolonies undergoing more limited membrane lipid remodeling following NaCl exposure. Finally, the combination of laser capture microdissection, RT-qPCR, and transcriptional fluorescent reporters analyzed by confocal microscopy revealed spatial heterogeneity of gene expression within microcolonies. Gene expression patterns varied according to cellular location within the structure, uncovering physiological regionalization whose nature depended on the biological functions examined. Collectively, these findings demonstrate that spatial organization confers emergent properties to foodborne pathogens, shaping their growth, metabolism, and stress tolerance. They highlight the importance of incorporating microbial spatial structuring into predictive microbiology frameworks and microbiological risk assessment strategies.