Effect of a natural organic acid-icing system on the microbiological quality of commercially relevant chilled fish species

Natural preservative organic acids (ascorbic, citric and lactic acids) were used to prepare a novel organic acid-flake icing system for the chilled preservation of hake (Merluccius merluccius), megrim (Lepidorhombus whiffiagonis) and angler (Lophius piscatorius). The icing system was prepared with two different concentrations of a commercial acid mixture-formula containing the three organic acids at 800 mg/kg and 400 mg/kg (C-800 and C-400 batches, respectively). Aerobic mesophiles, psychrotrophs, proteolytic bacteria, trimethylamine and pH were evaluated and the results compared with sensory analyses. Significantly (P < 0.05) lower counts of mesophiles were found for hake and megrim in the C-800 and C-400 batches compared with the control batch. In the case of angler, significantly (P < 0.05) lower counts of mesophiles, psychrotrophs and proteolytic microorganisms (P < 0.05) were found for fish stored in the C-800 icing conditions. Both C-400 and C-800 megrim batches exhibited significantly (P < 0.05) lower pH values than the control batch, and this result was also observed in the C-800 angler batch. Sensory analysis confirmed that the shelf lives of the three fish species in the C-800 batch were extended. According to the parameters assessed, storage of hake, megrim and angler in the proposed ice system better protects their microbial and sensory qualities. (C) 2011 Elsevier Ltd. All rights reserved.