The effects of quince seed mucilage film (QSMF) containing oregano (O) or thyme(T) essential oil on shelf life extension of rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage (4 °C) were evaluated over a period of 18 days. Films were prepared in four different concentrations of essential oils, including 0, 1, 1.5 and 2%. The control and the wrapped fillet samples were analyzed periodically for microbiological (aerobic and psychrotrophic count, Pseudomonas spp., H2S-producing bacteria, lactic acid bacteria, and Enterobacteriaceae), chemical (TBA, TVB-N, TMA-N), and sensory characteristics. Bacteria grew most quickly in trout fillets stored in air, followed by those wrapped with QSMF and the lowest counts were in wrapped samples with QSMF + 2%T. Pseudomonas spp., Enterobacteriaceae and LAB counts were significantly lower in samples wrapped with QSMF + 2%T. The lowest TBA value was obtained in fillets wrapped QSMF containing 2% oregano essential oil. The strong antioxidant activity of QSMF + 2%O was related to the composition of oregano essential oil. The GC analysis of essential oil components revealed that carvacrol (81.85%)was the major component of oregano essential oil. TBA value varied for all treatments and remained lower than 2 mg MDA/kg throughout storage. The formation of TVB-N, TMA-N increased with time of storage. TVB-N and TMA-N correlated well with the microbiological data, indicating that along with TVB-N, TMA-N may serve as a useful index for fillets spoilage. QSMF extended the microbial shelf life of rainbow trout fillets by 2 days, whereas the QSMF + 1%O, QSMF + 1.5%O, QSMF + 2%O, QSMF + 1%T, QSMF + 1.5%T and QSMF + 2%T resulted in a significant shelf life extension of the trout fillets by 3, 5, 9, 6, 10 and 11 days, respectively, as compared to the control samples.

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