Disinfectant-Based and Chlorinated Water Inactivation of Wild-Type Salmonella enterica Bacteriophages

Oral phage therapy is a promising strategy for reducing harmful bacteria in broilers. However, it may lead to the spread of therapeutic phages in the farm environment, potentially increasing bacterial host tolerance. To determine the stability of novel Salmonella bacteriophages in chlorinated drinking water and their response to farm disinfectants, we evaluated virucidal activity using a quantitative suspension test in the presence of organic matter. A >4-log-reduction was achieved using oxidizing agents, organic acid- and surfactant-based (1:350, 2 min), as well as glutaraldehyde and benzalkonium chloride-based (1:1000, 15 min) disinfectants. A hydrogen peroxide and peracetic acid-based disinfectant required a higher concentration (1:100, 10 min) to achieve an equivalent reduction. Results support the selection of disinfectants to mitigate residual therapeutic phages on farm premises. Chlorine (3-ppm, 24 h) did not reduce phage titer compared with the control, demonstrating the flexibility to administer bacteriophages in chlorinated drinking water for broilers.