ABSTRACT Background: Despite advances in food management, Salmonella infection (salmonellosis) remains a significant public health issue. The adverse effects of chemical preservatives and rising antibiotic resistance highlight the potential of phages with specific host ranges for biological food control.[1-3] Objective: This study aims to isolated a lytic phage against Salmonella enteritidis. Methods: The phage was isolated from Khorramshahr wastewater using the double-layer agar method. Its pH, UV, and thermal stability were determined, and the genome was sequenced. The effect of phages on eggs and milk contaminated with Salmonella Enteritidis was studied. Result: The isolated phage demonstrated stability across a pH range of 3-10 and lytic activity up to 60°C, with 15.55% survival after 30 minutes of UV exposure. Transmission electron microscopy and genome sequencing confirmed the phage belongs to the Caudoviricete family, with a genome measuring 43,215 bp and lacking virulence factors, CRISPR, and antibiotic resistance genes. When applied to contaminated eggs and milk, the phage significantly reduced microbial load by 82% and 94.8% after 48 hours at 37°C and 4°C, respectively. Additionally, phage survival in milk at 4°C was stable, decreasing by only 1 log after 72 hours. Conclusion: This study showcases a lytic phage from wastewater as a promising biocontrol agent against Salmonella enteritidis. Its stability under various conditions and significant reduction of microbial load in contaminated food highlight its potential for food safety. Additionally, the lack of virulence and antibiotic resistance genes supports its safety as an alternative to chemical preservatives for controlling foodborne pathogens.
