A bacteriophage cocktail can efficiently reduce five important Salmonella serotypes both on chicken skin and stainless steel

Abstract

Salmonella is one of the most important zoonotic pathogens and is mostly transmitted through food of animal origin. Application of bacteriophages is a promising tool to biocontrol Salmonella on both food and food contact surfaces. In this study, we evaluated the effectiveness of a six-phage cocktail for the reduction of Salmonella Enteritidis and a mixture of five major Salmonella serotypes (S. Enteritidis, Salmonella Typhimurium, Salmonella Infantis, Salmonella Paratyphi B, and Salmonella Indiana) on chicken skin and stainless steel. A phage cocktail with a final concentration of 107 PFU/cm2 was sprayed on these surfaces. After adding the phage cocktail, the samples were incubated at RT (~23°C) for different periods of time. The phage cocktail caused a significant reduction of S. Enteritidis and the mixed culture on chicken skin 30 min after phage addition, with 1.8 log10 and 1 log10 units, respectively. Reduction rates (1.2–1.7 log10 units) on stainless steel after 30 min were similar. Four hours after addition, the phage cocktail caused a significant reduction on both surfaces up to 3 log10 units on chicken skin and 2.4 log10 units on stainless steel. In a further experiment, bacteria added to stainless steel were not allowed to dry to simulate a fresh bacterial contamination. In this case, the bacterial count of S. Enteritidis was reduced below the detection limit after 2 h. The results demonstrate that this phage cocktail has potential to be used in post-harvest applications to control Salmonella contaminations.

Phenotypic characterization and genomic analysis of a Salmonella phage L223 for biocontrol of Salmonella spp. in poultry

“…For instance, treatment of contaminated chicken breast with a cocktail of five phages at MOI = 10 4 reduced the number of Salmonella Typhimurium by 2.0, 1.9, and 2.2 log CFU/piece at 2, 4, and 6 h, respectively 4 , 22 . Gvaladze et al, 2024 sprayed a cocktail of six phages on chicken skin contaminated with Salmonella Enteritidis and the mixed culture and achieved after 30 min a significant 1.8 log and 1 log reduction, respectively 55 . Spricigo et al, 2013 observed that dipping chicken breast for five minutes in a solution containing the bacteriophage cocktail and subsequently chilled at 4 °C for seven days showed significant 2.2 and 0.9 log10 cfu/g reductions in the concentrations of Salmonella Typhimurium and Salmonella Enteritidis, respectively 56 .…”