The effect of temperature on the bacterial load and microbial composition in Norway lobster (Nephrops norvegicus) tail meat during storage

Citation

Gornik SG, Albalat A, Macpherson H, Birkbeck H & Neil DM (2011) The effect of temperature on the bacterial load and microbial composition in Norway lobster (Nephrops norvegicus) tail meat during storage. Journal of Applied Microbiology, 111 (3), pp. 582-592. https://doi.org/10.1111/j.1365-2672.2011.05081.x

Abstract
Aims: The aim of this study was to update and extend our knowledge of the bacterial load and microbial composition in Norway lobster (Nephrops norvegicus) under commercially relevant storage conditions to optimize handling procedures. Methods and Results: Total viable counts were performed at different storage temperatures (0, 4, 8, 10, 12 or 16°C) and after different storage times (1-7 days). Storage at 16°C was found to be most detrimental, and storage at 0°C was found to be optimal. 16S-rRNA sequencing was utilized to determine the composition of the bacteria within the microflora. In this way, Photobacterium isolates, especially Photobacterium phosphoreum, were identified as the main specific spoilage organisms. The abilities to reduce trimethylamineoxide (TMAO) and to produce H2S were analysed in a selection of bacterial isolates. The higher the incubation temperature during storage, the more isolates were found to reduce TMAO and produce H2S. Conclusions: Nephrops norvegicus possesses an unusually high initial microbial load when fresh. Storage temperature is the most crucial factor affecting microbial growth, microbial activity and spoilage potential in N. norvegicus produce. Spoilage can be attributed mainly to P. phosphoreum. Significance and Impact of the Study: This study presents significant new findings with regard to the progression and causative agents of spoilage in N. norvegicus. Based on the results, we can recommend that N. norvegicus tails should be stored in a 0°C environment immediately after catch. Stored this way, the growth and spoilage activity of the microflora may be reduced significantly and an extension of shelf life might be attained.

Keywords
Nephrops norvegicus; Norway lobster; Photobacterium phosphoreum; shelf life; specific spoilage organism; spoilage; trimethylamineoxide

Journal
Journal of Applied Microbiology: Volume 111, Issue 3