Characterization and genomic analysis of Salmonella Weltevreden phage and its application to fresh chicken, beef, shrimp, and lettuce

Salmonella Weltevreden ( S. Weltevreden) is a common foodborne pathogen that can cause gastroenteritis in humans. With growing concerns about antibiotic resistance, phages have gained attention as a novel biocontrol strategy due to their advantages. However, no studies have reported the application of S. Weltevreden-specific phages in food systems. In this study, a new S. Weltevreden phage, SP-9-14, was isolated. SP-9-14 lysed 21 foodborne Salmonella serovars, had a 20-min latent period, and produced a burst size of 30 PFU/cell. Furthermore, SP-9-14 exhibited high thermal tolerance (5-65°C) and pH stability (pH 5.0-9.0). Whole-genome analysis classified SP-9-14 within the genus Agtrevirus (family Ackermannviridae ) and revealed no known antibiotic resistance or virulence genes. Finally, when phage SP-9-14 was applied to chicken, beef, shrimp, and lettuce samples contaminated with S. Weltevreden and stored at 4°C, the concentration of S. Weltevreden decreased by 0.33–1.56 log CFU/g, 0.77–3.16 log CFU/g, 0.89–4.47 log CFU/g, and 1.57–3.37 log CFU/g within 72 h. These results suggest that SP-9-14 is a promising candidate for biocontrol of S. Weltevreden in various food matrices under cold storage conditions.