The effects of superchilling on shelf-life and quality indicators of whole Atlantic cod and fillets

A newly developed industrial process was used to achieve superchilling of whole gutted cod on-board a fresh-fish trawler. It was compared to iced cod and after fillet processing, storage conditions at -1 degrees C and +1 degrees C were used to differentiate the groups. Quality difference was evaluated by microbial analysis, total volatile base nitrogen (TVB-N) and sensory evaluation. H2S-producing bacteria appeared to grow more rapidly in the fish that was iced whole compared to the samples that were superchilled on-board. Total viable counts in fillets were lower under superchilled storage conditions. The TVB-N level of fish iced on-board and stored chilled rose above the consumption limit on day 11 after catch, while the other samples were below. TVB-N levels where fillets were stored superchilled were still under the limit 16 days after catch, sensory evaluation however rejected both groups at that point. According to the sensory evaluation the effects of superchilled storage of fillets had a much greater impact on quality changes than the on-board cooling method, resulting in a 2-4 day extension of freshness period and 3 days longer shelf-life. The effects of on-board whole fish superchilling was less noticeable, however the method slowed the growth of H2S-producing bacteria and spoilage attributes.