Bacterial composition and succession during storage of North-Atlantic cod (Gadus morhua)at superchilled temperatures

• Main Authors: Reynisson, Eyjólfur, Lauzon, Hélène L, Magnússon, Hannes, Jónsdóttir, Rósa, Ólafsdóttir, Guðrún, Marteinsson, Viggó, Hreggviðsson, Guðmundur
• Format: Article in Journal/Newspaper
• Language: English
• Published: BioMed Central Ltd. 2009
• Subjects: atlantic cod; Gadus morhua; North Atlantic
• Online Access: http://www.biomedcentral.com/1471-2180/9/250

Abstract Background The bacteriology during storage of the North-Atlantic cod has been investigated for the past decades using conventional cultivation strategies which have generated large amount of information. This paper presents a study where both conventional cultivation and cultivation independent approaches were used to investigate the bacterial succession during storage of cod loins at chilled and superchilled temperatures. Results Unbrined (0.4% NaCl) and brined (2.5% NaCl) cod loins were stored at chilled (0°C) and superchilled (-2 and -3.6°C) temperatures in air or modified atmosphere (MA, % CO 2 /O 2 /N 2 : 49.0 ± 0.6/7.4 ± 0.2/43.7 ± 0.4). Discrepancy was observed between cultivation enumeration and culture independent methods where the former showed a general dominance of Pseudomonas spp. (up to 59%) while the latter showed a dominance of Photobacterium phosphoreum (up to 100%). Gas chromatography-mass spectrophotometry (GC-MC) showed that trimethylamine was the most abundant volatile in mid- and late storage periods. Terminal restriction polymorphism (t-RFLP) analysis showed that the relative abundance of P. phosphoreum increased with storage time. Conclusion The present study shows the bacteriological developments on lightly salted or non-salted cod loins during storage at superchilled temperatures. It furthermore confirms the importance of P. phosphoreum as a spoilage organism during storage of cod loins at low temperatures using molecular techniques. The methods used compensate each other, giving more detailed data on bacterial population developments during spoilage.