Inactivation of Salmonella Typhimurium in fresh cherry tomatoes using combined treatment of UV-TiO2 photocatalysis and high hydrostatic pressure

Abstract

The antibacterial efficacy of UV-TiO2 photocatalysis pre-washing in a water-assisted system (UVT, 4.5mW/cm(2), 5-15min) and high hydrostatic pressure (HHP, 300-500MPa, 1min at 25 degrees C) post-package combined treatment was evaluated against Salmonella Typhimurium inoculated onto whole cherry tomato surfaces and compared with chlorine disinfection (200ppm). An air pump was fitted at the bottom of UVT reactor to create turbulent flow for rotation of fruits for uniform disinfection. UVT-HHP combined treatment at 500MPa achieved bacterial reduction of more than 5 log via a synergistic effect, compared with chlorine disinfection. Lycopene and total phenolic contents and antioxidant activities were not significantly changed in tomatoes after any treatment. UVT-HHP combined treatment did not affect the surface color but caused softness in tomatoes. UVT pre-washing followed by HHP post-package treatment can be the effective intervention strategy alternative to conventional chlorine disinfection for production of ready-to-eat (RTE) fresh cherry tomatoes.