Combined effects of Zataria multiflora boiss essential oil and nisin on the shelf-life of refrigerated rainbow trout (Onchorynchus mykiss) fillets

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 degree C. 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), E sub(2) (treated samples with 0.4 % EO), N (treated samples with 150000 IU nisin/ kg), E sub(1) N (treated samples with Nisin and 0.2 % EO) and E sub(2) N (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 E sub(1) N and E sub(2) N 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.