Aluminum oxide films containing small quantities of silver are produced by plasma electrolytic oxidation of aluminum (97%) in different electrolytes aiming the synthesis of bactericidal coatings over aluminum for food packaging applications. Sodium citrate, citric acid, and sodium silicate, containing Ag nanoparticles (Ag‐NPs) or Ag+ ions (AgNO3) are tested as electrolyte. The galvanostatic anodization curves are used as diagnostic to evaluate the production of Ag‐alumina coatings in a one‐step procedure. Citric acid and silicate media provide more stability and reproducibility in coatings production; however, only coatings produced in silicate solution exhibit antimicrobial effect against Bacillus subtilis bacteria. The oxide films are characterized by scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (EDS). An irregular porous structure and a silver content of 0.1–1.9 wt.% in the oxide coatings are observed.