The efficacy of essential oils as natural preservatives in vegetable oil.

The efforts for finding the natural preservatives with nontoxicity and nonirritancy have encouraged the scientists to research among the medicinal plants. The preservative efficacy of Daucus carota, Ferula gummosa, Eugenium caryophyllata, Oliveria decumbens, Pelargonium graveolens, Ziziphora tenuir, Acorus calamus, and Trachyspermum ammi essential oils on challenge test's pathogens and on pathogen's inoculated vegetable oil was evaluated by antimicrobial effectiveness test. Carotol (46%), β-pinene (62.7%), eugenol (78.4%), thymol (50.6%), cis-asarone (27.5%), thymol (50.1%), and α-terpineol (19.5%) were the primary main components of D. carota, F. gummosa, E. caryophyllata, T. ammi, A. calamus, O. decumbens, and Z. tenuir essential oils, respectively. A. niger was more sensitive microorganism to oils. The antimicrobial activity of O. decumbens oil was the highest. Different concentrations of essential oils were added to the vegetable oil. The results of test on the vegetable oil showed that the combination of O. decumbens and P. graveolens oils (0.5:0.5%) had enough efficacies as natural preservative in vegetable oil.