The bacteria were cultured according to the plating method protocol. The single colony from the culture on the LB agar plate was inoculated into 10 mL of LB and then incubated at 37°C in an orbital shaker (220 RPM) overnight (about 16 hours). Next, the overnight cultures were refreshed by adding 7.5 mL of fresh LB medium to 2.5 mL of overnight culture and incubated for one hour at 37 °C. Then, the refreshed cultures were both diluted with LB to reach an optical density of around OD600 = 1.0 for E. coli (about 8.0 × 10 8 CFU/mL) (colony-forming units per mL), OD600 = 1.0 for Acinetobacter baumannii (about 5 × 10 9 CFU/mL), OD600 = 1.0 for Bacillus subtilis (about 1.0 × 10 8 CFU/mL), or OD600 = 1.0 for Staphylococcus aureus (about 5.0 × 10 9 CFU/mL). Afterward, the bacteria were diluted in PBS buffer solution with or without 0.5% (w/v) of adequate food dye to reach the initial concentration of 10 5 CFU/mL. Before 24 hours of incubation at room temperature with shaking (220 RPM), 100 μL of each solution was cultured onto LB agar plates. After incubation, another 100 μL of bacteria suspension was cultured on fresh LB agar plates to investigate if the food dyes affected bacterial growth. The remaining samples were transferred to sterile glass Petri dishes (45 mm diameter) and exposed to UV-C radiation for 1 minute inside the UV chamber. After the exposure, 100 μL of the bacterial suspension was cultured on fresh LB agar plates. In each case, the plate count method was used to determine the viability of the bacteria.