The Shelf Life of Farmed Turbot (Scophthalmus maximus)

Abstract

A total of 18 farmed turbot (Scophthalmus maximus) were slaughtered over 4 successive weeks in November 2012 and stored in polystyrene boxes with ice until analyzed. The fish were stored between 1 and 22 d and presented to a taste panel and further analyzed for quality index method (QIM), microbiological analysis by real-time quantitative PCR (qPCR), taste, pH, color by computer imaging, protein denaturation with differential scanner calorimeter (DSC), texture hardness, and shear force. Results show small, but significant changes in physical and visual attributes such as texture and color. No gaping was observed. Only small changes in texture were observed explained by lack of myosin denaturation. The fillets became more white and yellow during storage, whereas the major changes occurred during the 1st week. A panel evaluating QIM and taste could not distinguish major differences in appearance and taste and over 15 d storage period, but were able to quantify the age by smell. Analysis of microorganisms on the epidermis displayed growth of Carnobacterium maltaromaticum, potentially inhibiting growth of other spoilage bacteria. Fish stored for 22 d were rejected by the taste panel caused by a stale smell and taste, but not bitter or rancid. It is concluded that turbot has a shelf life of at least 16 d.Practical Application: This research gives a better understanding on why flatfish do have a long shelf life and the spoilage criteria involved. This understanding can be used to improve the shelf life of turbot even more, but more importantly increase the market potentials for this and other fish species.

Monitoring the freshness of fish: development of a qPCR method applied to MAP chilled whiting

“…Thus, double sequences recorded mostly in the early phase of shelf‐life could be explained by more than a single microbial species harbouring the torA gene. Another work quantified P. phosphoreum , thanks to TaqMan qPCR, during the storage of farmed turbot ( Scophthalmus maximus ) . Contrary to the results presented in our work, P. phosphoreum was not detected in turbot.…”

“…Another work quantified P. phosphoreum, thanks to TaqMan qPCR, during the storage of farmed turbot (Scophthalmus maximus). 43 Contrary to the results presented in our work, P. phosphoreum was not detected in turbot. However, many parameters could explain this fact, as Roth et al 43 studied the fish skin, with fish of a different species, which dwell in different habitats and were stored in different conditions.…”

“…43 Contrary to the results presented in our work, P. phosphoreum was not detected in turbot. However, many parameters could explain this fact, as Roth et al 43 studied the fish skin, with fish of a different species, which dwell in different habitats and were stored in different conditions. Additionally, contrary to what is commonly admitted in qPCR spoilage studies, 44 luxA, unlike torA, is not a gene directly 'related to the spoilage effect', as it encodes a luciferase.…”