Background: Chicken meat, as one of the most widely consumed sources of animal protein in Iran and worldwide, is characterized by high nutritional value. Controlling Salmonella contamination, a hazardous and persistent foodborne pathogen capable of transmission from raw chicken meat and food-contact surfaces to humans, is of considerable importance. The application of lytic bacteriophages denotes A new, low-cost, and low-risk biological control strategy that could significantly contribute to maintaining public health.
Objectives: This study aimed to investigate an optimal approach for applying a suspension of Siphoviridae bacteriophage against Salmonella Typhimurium contamination on stainless steel surfaces and chicken meat.
Methods: A Siphoviridae bacteriophage previously isolated and purified from an industrial poultry slaughterhouse in Tehran was employed. Phage activity against the host bacterium S. Typhimurium was verified through spot testing, and the optimal multiplicity of infection (MOI) was determined. The one-step growth curve was generated, and lytic activity at the optimal MOI was examined. Stainless steel and chicken meat samples were subjected to both preventive and corrective treatment protocols using spray and immersion methods at 12°C and 25 °C, simulating practical workplace conditions.
Results: Transmission electron microscopy (TEM) confirmed the phage as a member of the Siphoviridae family. The phage exhibited maximum efficacy at an MOI of 0.1, where lytic activity successfully suppressed bacterial growth for up to 10 h under in vitro conditions. The one-step growth curve revealed a latent period of 15 min and a burst size of 140 PFU/cell. In challenge experiments, corrective immersion treatment for 6 h resulted in the greatest reductions at 25 °C, with decreases of 2.52 log CFU/mL on stainless steel and 2.67 log CFU/mL on chicken meat relative to initial bacterial counts. After 12 h, the most substantial reductions were observed with corrective immersion at 12 °C, yielding decreases of 2.84 log CFU/mL on stainless steel and 2.18 log CFU/mL on chicken meat.
Conclusion: Siphoviridae bacteriophages demonstrated high efficiency in controlling Salmonella contamination. Among the evaluated protocols, corrective immersion treatment on stainless steel surfaces and chicken meat achieved the most effective outcomes compared with alternative approaches.