Combined effects of Zataria multiflora boiss essential oil and nisin on the shelf-life of refrigerated rainbow trout

The effects of Z. multiflora essential oil (EO) and nisin (N) on fresh rainbow trout (Onchorynchus mykiss) fillets were studied during 18 days storage at 4 ºC. Bacteriological and organoleptical evaluation were performed on fresh rainbow trout as the functions of treatment and storage time. Treatments included the following: A (control), E1 (treated samples with 0.2 % EO), E2 (treated samples with 0.4 % EO), N (treated samples with 150000 IU nisin/ kg), E1N (treated samples with Nisin and 0.2 % EO) and E2N (treated samples with nisin and 0.4 % EO). Total viable count (TVC) reached the value of 7 log cfu/g on days 9-12 for control sample and on days 15-18 for E1N and E2N samples. Meanwhile, in the sensory evaluation test, shelf life of rainbow trout fillets was 9 days for control samples and 12 days for other treated samples.