Effects of controlled thawing media temperatures on quality and safety of pre-rigor frozen Atlantic cod (Gadus morhua)

Novel strategies for thawing of pre-rigor frozen Atlantic cod (Gadus morhua) in water with air circulation, applying different and controlled temperatures are presented. After thawing (day 0) and after six days of storage at 2.9 ± 0.6 °C (day 6), quality parameters (thawing- and drip loss, cooking yield, sensory evaluation, and textural properties), chemical (pH, water content, total volatile basic nitrogen (TVB-N)) and microbiological analyses (total viable counts (TVC-IA), H2S-producing bacteria (H2S-IA), coliforms, thermo-tolerant coliforms and presumptive E. coli, and Listeria monocytogenes) were performed. The results obtained were compared statistically. Both thawing strategies, thawing at 10 °C and −0.5 °C or at constant 10 °C, preserved good quality fish. The hygienic conditions during the thawing processes were satisfactory and there were no indications of impaired food safety during any of the thawing strategies. No pathogens were detected in any of the cod samples, nor in the thawing media. The results showed that water thawing at −0.5 to 10 °C is suitable for frozen cod, without compromising quality and safety, and that no significant difference were seen between the selected thawing temperature regimes.