Use of citric and lactic acids in ice to enhance quality of two fish species during on-board chilled storage

• Citric and lactic acids were considered for the iced storage of hake and megrim.
• This strategy allowed the inhibition of microbial activity in fish on-board.
• The presence of both organic acids also increased sensory scores of chilled fish.
• Quality enhancement of hake and megrim was also observed during unloading.

This work focused on the on-board chilled storage of European hake (Merluccius merluccius) and megrim (Lepidorhombus whiffiagonis). To enhance fish quality, an aqueous solution including citric (1.25 g l−1) and lactic (0.50 g l−1) acids was prepared, frozen, ground and employed as icing medium. Its effect on sensory, microbiological and chemical changes was monitored after 9, 12 and 15 days of on-board storage. Lower (p < 0.05) bacterial growth was detected according to microbiological (aerobe, anaerobe, psychrotrophe, proteolytic, and Enterobacteriaceae counts) and chemical (trimethylamine content) assessments. An inhibitory effect (p < 0.05) on autolysis development (K value assessment) in hake was also detected. Finally, an enhancement of sensory scores (eyes, external odour and gills) in both species was obtained. Results described allow to conclude that on-board employment of such acid-mixture icing system can provide a profitable strategy to obtain higher quality and safe products while unloading.