A Novel Approach for Reducing Enteropathogens Using LAB-Fermented Whey Solution and UV-C Light-Activated Gallic Acid

This study evaluates the combined antibacterial activity (AA) of lactic acid bacteria (LAB) and UV-C light-activated gallic acid (AGA) against two common enteropathogens (Escherichia coli and S. Typhimurium) in terms of microbial growth and survival during gastrointestinal simulation (GS). The LAB were selected based on their capacity to ferment soy and whey concentrates in monoculture and co-culture. The resulting LAB-fermented medium (LABF) was evaluated for its antibacterial properties against enteropathogens and combined with AGA to determine its effects during the GS. Results indicated that the whey solution supported the highest growth of LAB co-culture (>107 CFU/mL). LABF showed AA in a dose-dependent manner, achieving >2-log reductions. Although AGA exhibited strong AA, when combined with LABF, its antimicrobial activity under GS was null, with a complete microbial recovery after 24 h of GS. Therefore, the application of LABF plus AGA in the in vitro gastrointestinal system needs further study to avoid loss of antibacterial activity during gastric transit.