Use of an eco‐friendly preservation technology as a strategy to increase the microbiological shelf‐life of a novel ready‐to‐eat salad containing vegetable by‐products

Abstract

The objective of this investigation was to evaluate different UV‐C irradiation doses in a novel ready‐to‐eat vegetable product containing vegetable by‐products (red beet leaves) and determine the microbiological shelf‐life and quality indicators during refrigerated storage (5 ± 1°C). During processing, no chemical disinfection was carried out and after the packaging step, 3 doses of UV‐C irradiation were applied (CTRL: 0 kJ/m2, L: 1 kJ/m2, M: 4 kJ/m2, and H: 7 kJ/m2) on the vegetable product studied (50% Creola purple lettuce, 25% beet leaves, and 25% arugula). It was observed that the intermediate dose (M) was the most suitable treatment since it could increase in six times its microbiological shelf‐life. Additionally, M was the one that showed the lowest loss of total polyphenols and the one that best maintained the antioxidant capacity (DPPH), probably attributed to the decrease in the activity of deterioration enzyme, PPO and higher ascorbic acid content at day 4. When evaluating % CO2/O2 on headspace of bags, UV‐C treatments reached earlier the dynamic equilibrium. Finally, all UV‐C irradiation treatments were successful against the simulated contamination. In that way, significant reductions of L. innocua and E. coli were found, with differences from up to 2 log cycles during storage. Finally, it can be concluded that UV‐C treatment can increase the microbiological shelf‐life of the novel ready‐to‐eat vegetable product, with quality indicators stabilization.Practical applicationsReady‐to‐eat salads present a short shelf‐life, which hinders their commercialization. As preservation technologies are required, UV‐C irradiation is an eco‐friendly alternative for its preservation as it has the potential to replace traditional disinfection treatments by reducing the water footprint of the total process. Therefore, since the UV‐C treatment is applied in the last step of the process (after packaging the product), microbiological contamination occurring in this type of vegetable products during processing is minimized. However, additional investigation is necessary to assess its suitability for a novel ready‐to‐eat salad containing horticultural by‐products.