Application of a Broad Range Lytic Phage LPST94 for Biological Control of <i>Salmonella</i> in Foods

<i>Salmonella</i>, one of the most common food-borne pathogens, is a significant public health and economic burden worldwide. Lytic phages are viable alternatives to conventional technologies for pathogen biocontrol in food products. In this study, 40 <i>Salmonella</i> phages were isolated from environmentally sourced water samples. We characterized the lytic range against <i>Salmonella</i> and among all isolates, phage LPST94 showed the broadest lytic spectrum and the highest lytic activity. Electron microscopy and genome sequencing indicated that LPST94 belongs to the <i>Ackermannviridae</i> family. Further studies showed this phage is robust, tolerating a wide range of pH (4&#8722;12) and temperature (30&#8722;60 &#176;C) over 60 min. The efficacy of phage LPST94 as a biological control agent was evaluated in various food products (milk, apple juice, chicken breast, and lettuce) inoculated with non-typhoidal <i>Salmonella</i> species at different temperatures. Interestingly, the anti-<i>Salmonella</i> efficacy of phage LPST94 was greater at 4 &#176;C than 25 &#176;C, although the efficacy varied between different food models. Adding phage LPST94 to <i>Salmonella</i> inoculated milk decreased the <i>Salmonella</i> count by 3 log₁₀ CFU/mL at 4 &#176;C and 0.84 to 2.56 log₁₀ CFU/mL at 25 &#176;C using an MOI of 1000 and 10000, respectively. In apple juice, chicken breast, and lettuce, the <i>Salmonella</i> count was decreased by 3 log₁₀ CFU/mL at both 4 &#176;C and 25 &#176;C after applying phage LPST94 at an MOI of 1000 and 10,000, within a timescale of 48 h. The findings demonstrated that phage LPST94 is a promising candidate for biological control agents against pathogenic <i>Salmonella</i> and has the potential to be applied across different food matrices.