Background: The aim of this study was to investigate the effects of chitosan coatings, oregano essential oil, and their combination on microbial quality of chicken fillet during 12 days in refrigerator temperature. Methods: Oregano oil was extracted by water distillation and then different concentrations of oregano oil (1% and 2%) were used for film preparation. Microbiological tests were carried out on the chicken fillet samples stored in 4 °C at different intervals including days 0, 3, 6, 9, and 12. Results: Treated groups with chitosan and oregano oil affected the increase rate of aerobic plate counts, coliform counts, and total psychrophilic counts significantly compared to the control group across the entire storage period (P < 0.05). Chitosan-based edible film containing oregano oil inhibited microbial growth on chicken fillet. Microbial populations were reduced by 2.14-3.53 log CFU/g in groups treated with chitosan and oregano oil. Our results revealed that incorporation of oregano essential oil at 2% concentration had the highest inhibitory effect on spoilage microorganisms in coated chicken fillet during 12 days of storage at refrigerator. Conclusion: Generally, application of oregano essential oil at 2% concentration had the potential to enhance safety and shelf-life of chicken fillet.

T HE present survey was performed to evaluate the effects of Colpomeni sinousa (C. sinousa) on melanosis, quality and lipid oxidation of Western Pacific shrimp (Litopenaeus vannamei) during the storage on ice. Shrimp samples were classified into four groups [Control, C. sinousa treatments (1 and 10%) and 3% sodium metabisulfite], packed and stored on ice for 20 days. Quality properties of shrimp samples were assessed daily. Sensory properties of fried shrimp samples were assessed at the end of the experiment. Peroxide, anisidine and TBA contents of shrimp samples were measured at days 0, 10 and 20 of the experiment using standard techniques. The highest qualitative scores were given to shrimp samples treated with sodium metabisulfite(3%), followed by C. sinousa extract (10%). Peroxide, anisidine and TBA contents of shrimp samples were significantly increase during the storage period (P <0.05) with the highest content for the control group. C. sinousa extract (10%) caused significant decrease in the production of peroxide, anisidine and TBA contents of shrimp samples during the storage (P <0.05). Sensory evaluators specified the highest sensory scores to hardness, color, taste and overall acceptance for the shrimp samples treated with sodium metabisulfite(3%), followed by C. sinousa extract (10%). Obtained findings were not statistically significant between shrimp samples treated with C. sinousa extract (10%) and sodium metabisulfite(3%). Therefore, considering the high cost of sodium metabisulphite, C. sinousa extract (10%) is an appropriate candidate to improve the shelf-life and oxidative stability of shrimp during the storage on ice.