Use of a bacteriophage cocktail to control Salmonella in food and the food industry

Abstract

The use of lytic bacteriophages for the biocontrol of food-borne pathogens in food and in the food industry is gaining increasing acceptance. In this study, the effectiveness of a bacteriophage cocktail composed of three different lytic bacteriophages (UAB_Phi 20, UAB_Phi78, and UAB_Phi87) was determined in four different food matrices (pig skin, chicken breasts, fresh eggs, and packaged lettuce) experimentally contaminated with Salmonella enterica serovar Typhimurium and S. enterica serovar Enteritidis. A significant bacterial reduction (>4 and 2log/cm2 for S. Typhimurium and S. Enteritidis, respectively; p≤0.005) was obtained in pig skin sprayed with the bacteriophage cocktail and then incubated at 33°C for 6h. Significant decreases in the concentration of S. Typhimurium and S. Enteritidis were also measured in chicken breasts dipped for 5min in a solution containing the bacteriophage cocktail and then refrigerated at 4°C for 7days (2.2 and 0.9log10 cfu/g, respectively; p≤0.0001) as well as in lettuce similarly treated for 60min at room temperature (3.9 and 2.2log10 cfu/g, respectively; p≤0.005). However, only a minor reduction of the bacterial concentration (0.9log10 cfu/cm2 of S. Enteritidis and S. Typhimurium; p≤0.005) was achieved in fresh eggs sprayed with the bacteriophage cocktail and then incubated at 25°C for 2h. These results show the potential effectiveness of this bacteriophage cocktail as a biocontrol agent of Salmonella in several food matrices under conditions similar to those used in their production.