The research was carried out in two separate experiments on fresh-cut carrot: The first experiment: the effect of different concentrations of Plantago psyllium mucilage (0, 100, 200, 400 mg/L) and four concentrations of essential oil of Zataria multiflora (0, 100, 250, 500 mg/L), separately and in combination in a factorial experiment on the basis of completely randomized design with 16 treatments and three replications was studied. The second experiment: the effect of essential oil and mucilage on the microbial load of fresh-cut carrot in the form of a split plot randomized complete block design with six treatments and three replications. The application of Zataria multiflora essential oil (500 mg/L), Plantago psyllium mucilage (400mg/L), and untreated control was considered as the main factor, while the time of microbial test in both the beginning and the end of the storage period was regarded as the minor one. Treated samples were packaged in polyethylene trays (175 ml) and were stored at 4°C. After 10 days of storage different parameters such as weight loss, total soluble solids (TSS), titratable acidity (TA), pH, color, and microbial contamination were investigated. The microbial load was evaluated in different aspect including mesophilic aerobic bacterial contamination, coliforms contamination, yeast and mold contamination, and the presence of E. coli. The results showed that the treatments had a significant effect on weight loss and increased carotenoid content. Different concentrations of essential oil and mucilage singly affected significantly titratable acidity, soluble solids and pH. Combination of treatments of 100 mg/l essential oil and 100 mg/l mucilage significantly reduced skin whitening of carrot fresh cut. Different treatments in terms of microbial contamination in all cases tested did not differ significantly. Only mold and yeast contamination increased significantly during storage, which was due to the interaction effect of treatments more pronounced in mucilage treatment. E. coli contamination was not observed in any of the samples. In essence, results of this study showed that the application of natural compounds of medicinal plants as edible coatings on fresh-cut carrot improves the quality and increases the shelf life. Also, these treatments, particularly the application of mucilage, have no effect on microbial contamination increasing.

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