Characterization of a novel Salmonella enterica serovar Manhattan phage and its inhibitory effects in vitro and in food matrices

Abstract

Salmonella enterica serovar Manhattan (Salmonella Manhattan) is an important foodborne pathogen that poses a significant threat to food safety and public health. Phage biocontrol is increasingly being utilized as a natural and eco-friendly approach to reduce bacterial contamination in the food chain, but there have been no reports of phages targeting Salmonella Manhattan. In this study, a novel phage targeting Salmonella Manhattan, designated vB_Sal_M467, was successfully isolated and characterized. Phage vB_Sal_M467 was able to lyse 12 different antibiotic-resistant Salmonella serovars. Morphological and genomic analysis revealed that phage vB_Sal_M467 belonged to the class Caudovirales and the genus Kayfunavirus. The 40, 111 bp double-stranded DNA genome encoded lysis-associated proteins, including endopeptidase Rz, holin, and lysozyme, but lacked virulence factors, antibiotic resistance genes, RNA-coding elements (tRNA/rRNA). Phage vB_Sal_M467 was stable over a wide range of temperatures (−20 °C–50 °C) and pH levels (3–11), and possessed a large burst size of 158.83 PFU/cell. In vitro bacteriolytic assays confirmed that phage vB_Sal_M467 effectively inhibited bacterial growth. Notably, significant antibacterial efficacy of phage vB_Sal_M467 against Salmonella Manhattan was observed in lettuce, milk, and apple juice at different temperatures (4 °C, 10 °C, 25 °C). Collectively, these findings highlight the potential of phage vB_Sal_M467 as a novel antibacterial agent for enhancing food safety.