Characterization of phenotypic and genotypic properties of Salmonella Typhimurium phages and their application as bioprotective agents in melon
摘要
The aim of this study was to characterize four different bacteriophages infecting Salmonella Typhimurium, and to reveal the possibility of their use in melon. The research results showed that the host ranges of vB_StypM-P01, vB_StypM-P03, vB_StypM-P04 and vB_StypS-P06 phages were quite wide and they were infective against S. Typhimurium, S. Enteritidis, S. Kentucky, S. Anatum, S. Gallinarum and E. coli strains. Morphological analysis revealed that the vB_StypM-P01, vB_StypM-P03 and vB_StypM-P04 phages belong to the Myoviridae family, whereas the vB_Styp-P06 phage belongs to the Siphoviridae family, and their genome size is 30–33 kb. None of the phages had pefA, sefC, spvC, sopE or gipA virulence genes in their genomes. Phages had low MOI values (0.1‒0.001), high adsorption rates (97.05‒98.50%), very low adsorption constants (6.45 × 10− 8‒ 9.52 × 10− 9 mL/min), short latent periods (10–20 min), high burst sizes (96–162) and low BIM values (1.06 × 10− 8‒ 4.14 × 10− 9). They maintained their stability under high temperature treatment (80 °C) and wide pH range (2‒12 pH). When used alone or in cocktail in food trials, they significantly reduced the number of S. Typhimurium in melon flesh and peels under storage conditions at 4 °C and 20 °C; and therefore, they have the potential to be used as biopreservatives in foods.