National Technical University of Athens, Greece
The aim of the study was to investigate the effect of nonthermal (high pressure/HP, osmotic dehydration/OD, pulsed electric fields/PEF) and minimal processing methods (surface decontamination) on the quality and shelf life of farmed gilthead seabream and European sea bass fillets during refrigerated storage.
Gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) fillets were treated using HP, OD or PEF as alternative approaches to the conventional post-harvest fish processing methods The incorporation of natural organic acids (i.e. lactic acid) at different concentrations in the washing water and/or in icing media was also tested for its efficacy to reduce initial microbial load and prolong shelf life. Samples were stored under controlled isothermal and variable conditions (0-15°C). Quality assessment was based on microbiological analysis (total viable count, Pseudomonas spp., Enterobacteriaceae spp.), pH, lipid oxidation, total volatile basic nitrogen, colour and texture measurement and sensory scoring.
The results of the study indicated that HP led to improved quality stability during subsequent refrigerated storage and significant shelf life extension (up to threefold), in terms of microbial growth, physicochemical and organoleptic degradation of fish. OD resulted in significant shelf life extension (7days and up to 18days for untreated and osmo-treated samples at 5°C, respectively). PEF enhanced the mass transfer phenomena during osmotic treatment but did not affect significantly the quality and shelf life of fish fillets. Initial surface decontamination up to 1.5logcfu/g by the addition of organic acids in the washing/icing water resulted in 2-3 days shelf life extension of fish fillets at 0°C.
The results of the study indicated that the application of nonthermal and minimal processing led to improved quality stability during subsequent refrigerated storage and significant shelf life extension, in terms of microbial growth, physicochemical and organoleptic degradation of the fillets.