Abstract

The aim of this research was to evaluate the effect of bacteriophage P22 on Salmonella Typhimurium in artificially inoculated tomato surface, under simulating condition of storage (10°C) and marketing (20°C) during seven days. First, we demonstrated the in vitro ability of phage P22 to reduce host population density to undetectable levels two hours after inoculation; however, S. Typhimurium was able to regrow up to 5.5 Log10CFU/ml after 24 h. S. Typhimurium-inoculated tomatoes stored at 10°C and exposed to P22 exhibited a mean bacterial reduction of 3.02 Log10CFU/tomato, while those stored at 20°C showed a mean reduction of 0.7 Log10CFU/tomato at day seven. Although phage P22 was able to reduce S. Typhimurium on tomato surface, the in vitro results indicate that a larger initial concentration of phages is required in order to ensure sustained inactivation of S. Typhimurium.

Key words: Biocontrol, bacteriophages, S. Typhimurium, tomato.