Food additives as photosensitizers: A systematic review and narrative synthesis

Photosensitizers are the key molecules determining the efficacy of anti-microbial photodynamic inactivation. However, photosensitizers for clinical use frequently fail to satisfy safety standards required by the food industry. A variety of strategies could be employed to address these issues i.e. focusing on photosensitizers with high efficiency (>3-log decrease in CFU), on food additives with minimal effects on food qualities (taste, texture, appearance, or nutrients), and also approved photosensitizers by regulatory authorities. This review summarizes 48 relevant studies that reported on the photodynamic activities of approved food additives. We report food additives with favorable photosensitive properties, which are capable of producing reactive oxygen species upon exposure to light at appropriate wavelengths, thereby inactivating various foodborne pathogens with great promise for food sterilization. The information presented in this systematic review may provide practical insights for implementation of photodynamic inactivation in industrial settings and encourage future development of food-grade photosensitizers for food sterilization.