The products fermented by lactic acid bacteria (LABs) are rich in metabolites that inhibit the growth of pathogens contributing in the conservation of foods, which may reduce or eliminate the use of chemical preservatives, making it possible to obtain “clean label” bakery products. In the present study, white breads using fermented milk (FM) were elaborated to study the preservative effect compared to a control formulation (C+) with additives (calcium propionate and improver) and ingredients (sugar, milk and fat), and a control formulation (C-) without them. FM (LABs=4.02±0.04logCFU/g) was obtained from the lactic fermentation by Lactobacillus acidophilus (LA-5®), Bifidobacterium (BB-12®) and Streptococcus thermophilus, and added during kneading at three concentrations (F1=25%, F2=37.5% and F3=50%), flour basis. Physicochemical analyses (pH, acidity) and microbiological analyses of identification (GRAM staining) and growth of LABs (agar MRS), yeasts and molds (agar PDA) were performed in sourdough and baked breads during storage at 20°C on days 1, 3, 5 and 7. The results indicate that the acidity in sourdough increases as the FM concentration increases, due to the production of lactic acid during fermentation, reducing up to 17% of pH level in F3(4.74) compared to C+(5.70). After baking, the concentration of LABs in breads decreased, but increased again during storage possibly to germination. The growth of LABs was observed from day 3 to day 7, reaching a maximum concentration of 6.89±0.04 logCFU/g in F3 that may be considered probiotic. As for microbiological stability, C- had a shelf life of 5 days while for the other formulations it was 7 days. The use of FM influenced (p<0.05) the growth of total yeasts and molds in bread: high concentrations of FM increased resistance to deterioration. The preservative effect of FM in F3 (2.05±0.02 logCFU/g) was even significantly higher than that of C+ (3.39±0.09 logCFU/g), with chemical additives.