To prove the efficacy of BB-stabilized phages in food preservation, we performed experiments simulating bacterial contaminations on the surface of lettuce leaves. E. coli BL21 and Salmonella enterica DSM 18522 (both Gram-negative) were used because these bacterial species are the most frequent contaminants of plant-based food. Lettuce leaves were cut with a sterile scalpel into 1.5 cm × 1.5 cm square pieces, and then 100 μL of 10 5 CFU/mL bacterial suspension (E. coli or S. enterica) was applied on the surface of the lettuce pieces. The pieces of leaves were left at room temperature until the suspension dried. Then, 100 μL of T4/P22 (against E. coli and S. enterica, respectively) phage suspension (about 10 6 PFU/mL) in TM buffer solution, or TM buffer with 0.5% BB was applied onto the surface of the lettuce pieces. As a control, a 100 μL of TM buffer solution was used. The samples were incubated for 25 minutes at room temperature, then exposed for 5 minutes to UV radiation within the laminar hood (Thermo Scientific MSC-ADVANTAGE; 36 W, 254 nm UV) and homogenized with the kitchen mortar. Homogenized samples were suspended in 1 mL of fresh TM buffer solution, from which 100 μL were cultured and incubated overnight on LB-agar plates at 37°C. After the incubation, colonies were counted.