Evaluation of bacteriophage cocktail as biopreservatives against Salmonella enterica serovar Typhimurium in chicken meat

Abstract

Salmonellosis is one of the most encountered foodborne illnesses worldwide caused by non typhoidal Salmonella enterica. Salmonella enterica serovar Typhimurium is one of the common serovars responsible for human and animal salmonellosis. As poultry meat acts as an important mode for transmission of human salmonellosis, bacteriophages-based decontamination of chicken meat was the objective of the study. Two bacteriophages were isolated against Salmonella enterica serovar Typhimurium and named as vB_StyS-PF79 and vB_StyS-RH55, respectively. The electron microscopy studies revealed that the phages belonged to the siphoviruses. The phages were found to be host specific and tolerated a wide range of temperature, and pH. Both the phages were observed to be sensitive to the chemical meat disinfectants viz. 2% lactic acid and 0.15% peracetic acid. Latent period of the phages vB_StyS-PF79 and vB_StyA-RH55 were found to be 20 and 10 min, and their burst size revealed ∼540 and 75 phages/cell, respectively. The phage, vB_StyS-PF79 alone could able to reduce bacterial count on day 1 in refrigerated poultry meat artificially spiked with S. Typhimurium. The phage cocktails yielded significant reduction in bacterial count on day 1 and 2 in artificially spiked poultry meat samples stored at 4 °C. Thus, the study concluded that the two isolated phages can be used as biocontrol agents against non-typhoidal Salmonella enterica serovar Typhimurium of poultry origin, effectively.