Simultaneous use of bacteriophages and UV irradiation for targeted control of bacterial pathogens using biocompatible food colorant brilliant blue FCF for selective protection of virions

Compared to the standard methods for treating bacterial diseases, bacteriophages are eco-friendly and chemical-free. Exposure to UV or sunlight hampers the efficacy of phage-based approaches. This is crucial when phages are i) exposed to sunlight (e.g., in agriculture) or ii) are to be used simultaneously with UV for sterilization. Here, we develop a method utilizing a food dye, brilliant blue FCF (BB), that selectively stabilizes bacteriophages against exposure to UV irradiation without protecting Gram-negative bacteria. Simultaneous action of BB-stabilized bacteriophages and UV allow for the removal of up to 99.99% of bacteria within only 30 to 60 minutes. We explain the mechanism of protection, which requires selective binding of BB to the capsid. We demonstrated the method's applicability in combating biofouling of membranes and food sterilization. We envision using the developed approach against biofouling in industrial processes, in agriculture (e.g., against Erwinia amylovora, Pseudomonas syringae, and Xylella fastidiosa), and the food industry.