Effect of a twoastep natural organic acid treatment on microbial activity and lipid damage during blue whiting (Micromesistius poutassou) chilling

Quality loss inhibition in chilled blue whiting (Micromesistius poutassou) was investigated. For it, a natural organic acid-mixture including ascorbic, citric and lactic acids was applied in a two-step processing strategy: (i) as an aqueous dipping medium previous to chilling storage and, (ii) included in the flake ice employed as chilling system. As a result of the acid-mixture addition, a partial inhibition of microbial and biochemical mechanisms involved in the quality loss was obtained. Thus, aerobe and psychrotrophe counts in treated fish showed lower ranges (2.07-4.15 and 2.43-4.39logCFUg-1, respectively) than control fish (2.64-5.83 and 2.30-5.30logCFUg-1, respectively). Sensory analysis revealed that treated fish was still acceptable at the end of the experiment (day 9), while control fish was rejected at this time. Lipid hydrolysis (free fatty acid formation) proved to be more limiting of fish quality than lipid oxidation (peroxide and thiobarbituric acid-reactive substance formation).