Safety improvement and quality retention of gamma irradiated spinach leaves

Abstract

The purpose of this work was to evaluate γ‐irradiation effects on native microbiota, some phytochemicals and sensory attributes of fresh spinach (Spinacia oleracea L.) throughout 15 days of storage (6 °C ± 1 °C). The proposed treatment (1.5 kGy) effectively reduced native microbiota extending shelf life under refrigeration to 14 days, and the evaluated phytochemicals (polyphenols, compounds with antioxidant capacity, chlorophyll, carotenoids) were preserved with the exception of ascorbic acid, which was reduced by more than 80% after treatment. Sensory acceptability, evaluated by a consumer panel, of samples irradiated either at 1.5 or 3.0 kGy was good till the last analysis date (day 14). The target dose had a great performance, presenting scores in some attributes significantly higher than those of control samples (overall liking and appearance on day 2). Overall, the performance of gamma rays was acceptable and significantly increased product acceptability; therefore, it represents a feasible alternative for spinach disinfection. Practical applications Gamma irradiation has attracted attention as a potential nonthermal decontamination strategy to ensure the safety of fresh fruits and vegetables. Several studies have demonstrated the high efficiency of this technology applied on different vegetables to control typical pathogens, but vegetables tolerance to radiation can vary, so process validation is required in each case. Hopefully the results presented herein could encourage large‐scale adoption of this technology by the fresh produce industry.

The public health risk posed by Listeria monocytogenes in frozen fruit and vegetables including herbs, blanched during processing

“…Several studies have demonstrated the high efficiency of this technology applied on different vegetables to control pathogens, but vegetables tolerance to radiation can vary, and irradiation temperature may have an impact, so process validation is required. At À20°C, radiation doses sufficient to achieve a 5-log 10 reduction (3.9-4.6 kGy) caused significant softening of peas and broccoli stems but not of corn or lima beans (Niemira et al, 2002;Finten et al, 2017). The consumer perception of foods treated with irradiation may be negative.…”