Updated project metadata. Lactobacillus Bulgaricus (CIRM-BIA1592) adaptation to cow milk versus soymilk environments was studied thanks to proteomics. Bacteria were harvested at the begining of stationary phase. Protein trypsin digestion were performed in solution. The data set contains 22 files of NanoLC-MS/MS analysis, acquired on a Qexactive mass spectrometer. Design: 2 classes (cow milk, soymilk), 4 biological replicates for cow milk, 3 biological replicates for soymilk. All samples were injected at least 3 times.