Running title: Enhanced shelf-life of hake stored in slurry ice

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Slurry ice, a biphasic system consisting of small spherical ice crystals surrounded by seawater at subzero temperature, was evaluated as a new chilled storage method for European hake (Merluccius merluccius), a gadoid fish species of remarkable commercial interest, an compared with a control batch stored for 19 days in traditional flake ice. The results obtained in the sensory analysis indicated a significant extension of shelf-life, from five days (flake ice batch) to 12 days (slurry ice batch), this correlating well with the observed microbial activity. Initial total volatile base-nitrogen concentrations of 22.69 mg/100 g muscle at day 0 were maintained in the slurry ice batch along storage, but rose to 47.42 mg/100 g muscle in the flake ice batch after 19 days of storage. Significant differences in the trimethylamine concentrations after 19 days of storage were also observed between the slurry ice batch (3.97 mg/100 g muscle) and flake ice batch (11.54 mg/100 g muscle). Significantly lower counts of total aerobes and proteolytic bacteria were also attained in hake muscle stored in slurry ice, microbial numbers reaching differences above 2 or 3 log units, respectively, after 19 days of storage. The slurry ice batch exhibited a significantly lower increase in the pH value (0.2 units), as compared to the flake ice batch (1.1 units), this also indicating a better control of alkalinising microflora. According to the parameters assessed, storage of European hake in slurry ice extended its shelf-life and allowed a better maintenance of sensory and microbiological quality.