Influence of sodium chloride and modified atmosphere packaging on microbiological, chemical and sensorial properties in ice storage of slices of hake (Merluccius merluccius)

The effect of an optimum gas mixture (50% CO2:45% N2:5% O2) on hake slices (Merluccius merluccius) was studied when combined with a sodium chloride dip (5 min in 5% NaCl solution). Exudation, water binding capacity (WBC), microbial growth, as well as undesirable chemical (pH, total volatile bases, lipid oxidation), and sensory alterations (raw fish odour) cooked fish flavour), were monitored. Values were compared with those obtained for air-stored samples and for MAP-stored samples in the absence of NaCl. Sodium chloride dips showed a further inhibition of biochemical, microbiological and sensory deterioration of MAP-stored hake slices, so that total volatile bases and total viable counts values were significantly lower (p<0.05) than in fish stored under MAP conditions throughout all storage periods, and sensory properties were scored significantly higher. Exudation was also reduced in MAP-stored fish when previously dipped in sodium chloride solutions. Consequently, the shelf-life of hake slices was extended for 2 days when stored under MAP conditions, and for 8 days if dipped in sodium chloride solutions prior to MAP storage.