AbstractBackground and ObjectivesBread may be spoiled by mold, which results in major economic losses. The aim of this study was to optimize the anti‐mold properties of apple juice fermented with Propionibacterium freudenreichii to get high levels of propionic acid with lesser amounts of acetic acid, which impairs bread taste.FindingsAfter fermentation for 7 days at 35°C, apple juice (half‐diluted to about 4% fermentable sugars; with 1% yeast extract; pH adjusted to 6.0) contained 1.0% propionic acid and little amounts of acetic acid (about 0.35%).ConclusionsIn bread, the anti‐mold activity of fermented apple juice (5%, fb) was similar to that of apple cider vinegar (2.44%, fb).Significance and NoveltyFermented apple juice is a novel mold inhibitor for bread that may replace apple cider vinegar and part of calcium propionate.