MAP packaging with essential oils vapours increases the shelf-life of refrigerated sea bream fillets

Resumen

The demand for fresh MAP packaged sea bream fillets has increased significantly over the past few years. But, shelf-life of sea bream fresh fillet is relatively short because fish are susceptible to microbiological deterioration. Thereby, there is a growing tendency to apply new preservation methods, allowing shelf-life extension of fresh fish fillets. Essential oils are secondary metabolites of plants that are generally recognized as safe and they have a demonstrated effect as antimicrobial. Thereby oregano essential oil (OEO) has been studied for its antimicrobial and antioxidant activity in various commercial or model foods, e.g., raw and cooked chicken, beef, and fish. The problem of use of essential oils as antimicrobial is that, normally, they must be used in concentrations relatively high and can produce undesirable sensorial changes in the food. Therefore, the research in the use of this natural essential oils as antimicrobials must be focused in new applications techniques allowing the reduction of the doses in the food, as the application of essential oils vapours and nanoemulsions. For this reason, the aim of this study was to evaluate the antimicrobial effect of the OEO vapour and nanoemulsion applied on sea bream fillets packaged using the modified atmosphere packaging (MAP) technique. The OEO vapors were applied using a patented device developed by our laboratory. The results showed that fillets processed and packaged under ultraclean conditions extended the shelf-life of the MAP packaged fish stored at 4ºC. In addition, both methods used for applying the antimicrobial oregano essential oil (nanoemulsion surface decontamination before MAP packaging, and vapour application during MAP packaging) helped to control microbial spoilage in a better way than only ultraclean conditions. In this study, the results of microbial analyses indicated that OEO treatments represent a good alternative for extend the shelf-life of sea bream fillets up to 3 weeks (MAP packaged and stored at 4ºC). The advantage of using essential oil vapors during MAP packaging is that washing (for surface decontamination) of fillets before MAP packaging is not necessary, saving a preparation operation of the fillets and the corresponding costs.