In-package cold atmospheric plasma processing for shelf-life extension of gilthead seabream (Sparus aurata) fillets

In-package cold atmospheric plasma (CAP) processing, which refers to the generation of CAP inside a sealed package, enables a local disinfecting reaction, allowing no post-process contamination and extending the shelf-life (SL) of perishable food products, such as fresh fish. In the present study, four in-package CAP treatments, differing in frequency and processing time, were applied on fresh gilthead seabream (Sparus aurata) fillets, prepacked in low-permeability pouches. Fish SL was evaluated during isothermal storage at 2°C, whereas untreated packaged fillets were used as control samples. The SL assessment of the fish fillets was based on microbial enumeration of total aerobic mesophilic count (TMC), total aerobic psychrotrophic count (TPC), Pseudomonas spp., Enterobacteriaceae, and lactic acid bacteria (LAB), pH measurement, determination of color and texture parameters, lipid oxidation, total volatile basic nitrogen (TVB-N) measurement, and sensory evaluation. All CAP treatments were effective against microbial inhibition in fish fillets, especially regarding TMC, TPC, and Pseudomonas spp., resulting in maximum reduction of 1.49, 1.24, and 1.43 log CFU/g, respectively, compared to the control samples after 16 days of storage. However, minor effect was observed against Enterobacteriaceae and no effect against LAB. CAP processing did not affect the color and texture parameters of fish fillets, and TVB-N production was slightly reduced in CAP-treated samples; however, lipid oxidation was accelerated, especially at the more intense processing conditions, by a maximum of 75.5%. The results of the study indicated that in-package CAP processing could be effectively applied for inhibiting spoilage during refrigerated storage and extending SL of fresh fish fillets. PRACTICAL APPLICATION: In-package cold atmospheric plasma (CAP) processing was tested on gilthead seabream fillets, a highly perishable product with high commercial potential if its shelf-life can be extended through minimal processing. The food industry could benefit from in-package CAP technology as it is a cost effective nonthermal processing method while preventing post-processing contamination of the products. Although in-package CAP processing has not been extensively tested on fish, this study examined the quality and shelf-life of a highly perishable fish species, and the results could be further used as a reference for processing optimization of the CAP treatments.