Shelf Life of Leafy Vegetables Treated with Natural Essential Oils

Essential oils as natural sanitizing agents were sprayed on Swiss chard leaves produced by organic methods. Samples were stored at 0 and 5°C and 97% to 98% relative humidity. Microbial populations, peroxidase activity, and sensory attributes were monitored during storage. No significant differences were observed between treated and control samples stored at 0°C. However, samples treated with the essential oils of eucalyptus, tea tree, and clove and stored at 5°C presented microbial counts significantly lower than those of control samples. The essential oils of eucalyptus, tea tree, lemon, rosemary, and clove presented peroxidase activity inhibition that, in the case of eucalyptus, increased to 65% during storage. Although some of the essential oils did appear to reduce microbial counts and peroxidase activity compared with controls, they were not effective in extending the shelflife of the Swiss chard leaves from a sensory point of view.