The combined effects of ultraviolet-C irradiation and modified atmosphere packaging for inactivating Salmonella enterica serovar Typhimurium and extending the shelf life of cherry tomatoes during cold storage

Abstract

Abstract The combined effects of ultraviolet-C (UV-C) irradiation, modified atmosphere packaging (MAP), and cold storage temperature on the quality of inoculated (Salmonella enterica serovar Typhimurium) and non-inoculated cherry tomatoes were investigated. Based on the inactivation and sublethal injury tests of S. Typhimurium by UV-C irradiation, 2 kJ/m2 UV-C was selected for the combined treatment. Non-inoculated and inoculated cherry tomatoes were irradiated with 2 kJ/m2 UV-C and then packaged under two different modified atmosphere conditions (passive and active) and stored for 9 d at 4 and 20 °C. As controls, non-irradiated cherry tomatoes packaged in perforated film bags were stored. When the inoculated cherry tomatoes that were irradiated with UV-C were packaged under an active modified atmosphere (5.3% CO2 + 5.5% O2), the S. Typhimurium populations were significantly reduced during storage at 4 °C compared to those of other treatments. Regarding the color, the combination of UV-C and active MAP delayed the change of Hunter b* and ΔE values in cherry tomatoes during storage at 4 °C. Regardless of treatment and packaging method, the cherry tomatoes stored at 4 °C exhibited a lower decrease of firmness compared to those stored at 20 °C. After 9 d of storage at 4 or 20 °C, there were significant differences in lycopene content and weight loss depending on storage temperature or gas composition in packaging film. Therefore, these results suggest that the combination of UV-C irradiation and active MAP can improve the microbial safety and extend the shelf life of cherry tomatoes during cold storage.