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 ۱۸ days storage at ۴ 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), E۱ (treated samples with ۰.۲ % EO), E۲ (treated samples with ۰.۴ % EO), N (treated samples with ۱۵۰۰۰۰ IU nisin/ kg), E۱N (treated samples with Nisin and ۰.۲ % EO) and E۲N (treated samples with nisin and ۰.۴ % EO). Total viable count (TVC) reached the value of ۷ log cfu/g on days ۹-۱۲ for control sample and on days ۱۵-۱۸ for E۱N and E۲N samples. Meanwhile, in the sensory evaluation test, shelf life of rainbow trout fillets was ۹ days for control samples and ۱۲ days for other treated samples.