Antimicrobial Effectiveness of Gelatin-Alginate Film Containing Oregano Essential Oil for Fish Preservation

This study aimed to evaluate the effect of gelatin-alginate film containing 1.5% oregano essential oil (OEO) on the shelf life of rainbow trout (Oncorhynchus mykiss) slices during refrigerated storage over a period of 15 days. The blend film was prepared at 75% fish gelatin to 25% sodium alginate ratio and OEO was added to the film formulation. All the treatments (the control and wrapped slices) were analyzed periodically in terms of microbiological factors (total viable count, psychrotrophic count and spoilage microorganism, such as lactic acid bacteria, Pseudomonas spp. and Enterobacteriaceae). In addition, the samples were analyzed in terms of total volatile base nitrogen (TVB-N) and pH. Use of the OEO-blend film delayed bacterial growth throughout 15 days of storage compared with the control and slices treated with blend films without OEO (P<0.05). The lowest TVB-N and pH levels were 59.98 and 6.75, respectively, in OEO film at the end of the storage. Therefore, this study showed that OEO-blend film was an effective antimicrobial suitable for the potential food packaging applications. Practical ApplicationsDevelopment of edible films incorporated with essential oils is an attractive option for improving packaging food. In this study, the effect of gelatin-alginate edible film containing oregano essential oil (OEO) on spoilage bacteria was investigated. Strong antimicrobial effect of OEO and restricted access of oxygen by films make gelatin-alginate film incorporated with OEO suitable for fish packaging.