This project investigates the proteomic response of Pseudomonas aeruginosa PAO1 and Staphylococcus aureus to postbiotic metabolites derived from Lacticaseibacillus rhamnosus. Bacterial cultures were exposed to sub-MIC concentrations of L. rhamnosus cell-free supernatant (CFS) or lactic acid (LA) for 6 h, and intracellular proteins were extracted for quantitative label-free proteomics using HPLC–MS/MS. The dataset includes RAW mass spectrometry data and MaxQuant output files. The aim of this study is to compare stress responses triggered by complex postbiotic mixtures versus LA alone, focusing on antimicrobial and antibiofilm potential.