Novel Enterococcus Phages Identified through Comprehensive Screening to Control Contamination in Chicken Meat

Abstract

BACKGROUND Antibiotic-resistant Enterococcus faecalis and E. faecium are persistent contaminants in food and environmental settings, including poultry-related matrices, contributing to food safety risks and antimicrobial resistance (AMR) dissemination. This study aimed to identify Enterococcus phages through environmental screening and evaluate their biocontrol potential using a chicken wing food model. RESULTS From 1719 environmental samples, 45 Enterococcus-targeting phages were isolated, and two (Efs.1 1-1 and Efm 3-10) with the broadest lytic profiles were selected for characterization. Transmission electron microscopy revealed that both phages belong to Caudoviricetes with siphovirus-like morphology, latent periods (6-8 min), and high burst sizes (90-110 PFU per cell). Whole-genome sequencing revealed complete circular genomes with estimated completeness values between 0.97 and 1.00, and no detectable virulence, lysogeny, or AMR genes. The phages were stable at pH 4 for 60 min and tolerated 40-60 degrees C for 1 h. Phage titers decreased from 10.0 to no less than 6.0 log PFU mL(-1) across all storage conditions over 12 months. In vitro assays in tryptic soy broth showed that while the control groups reached 8.56-9.12 log CFU mL(-1) at 24 h at 37 degrees C, no bacteria were detected in any of the phage-treated samples (limit of detection: 1 CFU mL(-1)). In the chicken wing food model, phage treatment maintained bacterial counts below the detection limit (<1 log CFU g(-1)) throughout refrigerated storage. Mean log reductions reached 1.78-2.78 and 3.71-4.71 log CFU g(-1), respectively. CONCLUSION These novel lytic phages exhibit strong stability and rapid antibacterial activity, offering promising biocontrol agents to reduce Enterococcus contamination in chicken meat.