Isolation and Characterization of Bacteriophages Targeting <i>Salmonella</i> spp. in Meat: Efficacy, Stability, and Application as a Biocontrol Agent

Abstract

Background: Microbial spoilage of food and foodborne diseases pose significant challenges to the food industry. Bacteriophages offer a promising biological alternative for biocontrol methods in addressing these issues. Objectives: Our study focuses on the isolation and evaluation of the phage PhSal for controlling Salmonella spp. contamination in meat. This research examines the potential of PhSal as a biocontrol agent in food safety. Methods: Five phages were isolated from wastewater samples. To determine the optimal multiplicity of infection (MOI), the phages were incubated with bacteria at a concentration of 107 CFU/mL at 37°C, and measurements were taken every 30 minutes for one hour. Additionally, the stability of the phages was evaluated across a temperature range of 30 - 80°C and a pH range of 2 - 13. Subsequently, the PhSal06 phage was employed as a biocontrol agent in meat samples at two temperatures: Four centigrade degrees and 25°C. Results: Antimicrobial activity was assessed by inoculating sterilized meat with bacteria (104 CFU/mL; colony-forming units per mL) and phages (108 PFU/mL; plaque-forming units), with bacterial counts measured over 96 hours. The isolated bacteriophages (PhSal01, PhSal04, PhSal06) had polyhedral heads and contractile tails, belonging to the Myoviridae and Siphoviridae families. They showed latency periods of 10 - 25 minutes, stability at pH 4 - 12 and temperatures up to 60°C, and optimal antibacterial activity at higher phage MOIs. PhSal06 effectively reduced Salmonella enterica Sal03 in meat at 4°C, achieving complete lysis after 24 hours. Conclusions: The isolated bacteriophage PhSal06 effectively controlled S. enterica Sal03 in meat, demonstrating stability across a wide pH and temperature range. It achieved complete bacterial lysis at 4°C, underscoring its potential as a biocontrol agent in food safety applications.