Reduction of microbial contamination of fruits and vegetables by hypericin-based photosensitization: Comparison with other emerging antimicrobial treatments

• Study is focused on decontamination of fruits/vegetables by photosensitization.
• Data indicate that treatment efficiency is comparable with that of pulsed UV light.
• No thermal effects or impact on antioxidant activity of fruit/vegetable were found.
• Photosensitization has potential as environmentally friendly, non-thermal preservation technology.

The aim of this study is focused on the evaluation of possibility to control microbes on the surface of fruits and vegetables (FV) by hypericin (Hyp)-based photosensitization. The effect of Hyp-based photosensitization on survival of Bacillus cereus in vitro and on the surface of FV was examined using different Hyp concentrations (1.5 ⋅ 10−5–1 ⋅ 10−8 M) and illumination (0–9.2 J/cm2; λ = 585 nm; intensity – 3.84 mW/cm2). Results indicate that Hyp-based photosensitization effectively (4.4 log CFU/mL) reduces the population of Bacillus in vitro. Inactivation of mesophilic bacteria on the surface of FV reached 0.6–0.72 log CFU/g and was comparable with that of high power pulsed light (HPPL) treatment. No significant increase of temperature was detected on the surface of treated FV. Data reveal that this treatment has no significant impact on antioxidant activity and color of treated FV and was comparable with the effects of HPPL. Hyp-based photosensitization as nonthermal, environment-friendly and cost effective antimicrobial treatment seems promising for development of innovative preservation of fruits and vegetables.