Photodynamic inactivation (PDI) of microorganisms is a promising process in the food industry, as its non-thermal nature and wide range of action allow for cheaper and effective removal of various types of bacteria. PDI is based on the combination of visible light, a photosensitizer (PS) molecule, and molecular oxygen. Once illuminated correctly, the PS will react with molecular oxygen and produce reactive oxygen species (ROS), which will act on the microorganism through different paths, killing them. Most of the in vitro PDI studies have shown significant antimicrobial effects against several foodborne bacteria, while studies on food matrixes are still few, but very promising. This chapter aims to explain the PDI process and its potential application on the food industry.