Post-harvest application of bacteriophages to reduce Salmonella on poultry products and contact surfaces

Abstract

Bacteriophages (phages) are natural viral predators of bacteria and offer a promising alternative to conventional antimicrobials for improving food safety. This dissertation focuses on the post-harvest application of phages to reduce Salmonella enterica contamination in poultry products and on contact surfaces.

Six virulent phages were isolated and characterized regarding host range, efficiency of plating (EOP), and stability. Reduction experiments in vitro demonstrated that some phages achieved significant decreases in bacterial counts, even at low multiplicities of infection (MOIs). Based on these results, a phage cocktail was developed and tested against five Salmonella serotypes. The cocktail achieved higher reductions than individual phages, remaining effective across a range of temperatures.

Further application trials on chicken skin, stainless steel, and in pilot-scale carcass experiments confirmed reductions of up to 2–3 log units, highlighting the potential of phages as practical biocontrol tools. While challenges remain in scaling laboratory results to industrial conditions, the findings underline the relevance of phages as an innovative measure for enhancing poultry safety within integrated food safety strategies.