Synergistic Antimicrobial Activity by Light or Thermal Treatment and Lauric Arginate: Membrane Damage and Oxidative Stress

This study highlights an effective antimicrobial processing approach using a novel combination of lauroyl arginate ethyl (LAE) and two different physical treatments, light (UV-A) and mild heat. Both combinations demonstrated synergistic inactivation against a model Gram-negative bacterium or a Gram-positive bacterium or both by a >5-log reduction. Further mechanistic study revealed that oxidative stress is responsible for synergistic inactivation between LAE and UV-A, while both membrane damage and oxidative stress are responsible for the synergistic combination between LAE and mild heat. The mode of action of LAE was further compared to that of polymyxin B and analyzed using artificial membrane model systems and the addition of antioxidants. The proposed combination of LAE and common physical treatments may improve food preservation, food safety, and current sanitation processes for the food industry and the inactivation of pathogenic strains in biomedical environments.