Novel technique for treating grass carp (Ctenopharyngodon idella) by combining plasma functionalized liquids and Ultrasound: Effects on bacterial inactivation and quality attributes

A novel technique for treating grass carp by combining plasma functionalized liquids and ultrasound to inactivate bacteria was developed. The effects of the plasma functionalized liquids (PFL) including plasma functionalized water (PFW) and buffer (PFB) and their respective combination with ultrasound treatment (USPFW and USPFB) on the oxidative and physical qualities of grass carp were also investigated. Individual applications of PFW and PFB significantly reduced the populations of Escherichia coli and Shewanella putrefaciens in the range of 0.31–1.18 log CFU/g, compared with the control with a reduction of 0.18 log CFU/g, while combined treatments of USPFW and USPFB presented additional reductions of 0.05–0.65 log CFU/g, with potential synergy demonstrated for PFW and ultrasound. The treatment resulted in improved biomedical index and nutritional value of fatty acids and lipids, protein structural unfolding, increased lipid oxidation and protein degradation with values within the acceptable limits, and the combined treatment was more effective for retarding the hardness reduction in grass carp, while the colour change was also significantly affected, resulting in increased whiteness. The results indicated that the combined treatments may be a promising approach to improving the quality of seafood products.