Effects of different on-board cooling methods on the microbiological and sensory quality of Baltic herring (Clupea harengus L.)

In Finland, Baltic herring is mostly cooled on board the vessel in containers with ice and ambient sea water. In this study, the effect of three different cooling methods on the microbiological and sensory quality of Baltic herring were studied. At the end of August, eighteen containers (6 containers/method) of Baltic herring were chilled on board by (1) the conventional cooling system with ice and sea water, (2) cooling with ice and pre-cooled sea water or (3) cooling with ice and pre-cooled 1.2% NaCl water. Containers were stored in cold room for six days and samples were analyzed one, four and six days after catching. The microbiological quality was studied by analyzing the fish skin swab samples by cultivation and impedance method. Sensory qualities like taste, odor and texture were evaluated by a panel of eight people. The quality differences were analyzed by hierarchical analyses of variance. After 6 days of cool storage, the cooling method of ice with pre-cooled 1.2% NaCl produced the best sensory quality.