Effect of ultraviolet light treatment on microbial contamination, some textural and organoleptic parameters of cultured sea bass fillets (Dicentrarchus labrax)

Abstract

Ultraviolet (UV) light (λ = 250 nm) was assessed to increase shelf life of sea bass ( Dicentrarchus labrax ). Fillets were exposed to different doses: i) 7.9 kJ/m 2 , designed as UV 8 , ii) 15.8 kJ/m 2 , UV 16 and iii) control, untreated (C). After the treatments, the fillets were stored in a cold-room (4 ± 1 °C) up to 11 days and sampled at 0, 2, 4, 7, 9 and 11 days. The UVL treatments significantly decreased microbial counts during the first 4 days post-mortem (dpm), independently of the doses, compared to C fillets. A delay in rigor process in both UV 8 and UV 16 fillets was observed, as well as consistent improvement of textural parameters (hardness, gumminess and chewiness) at 11 dpm. These findings correlate with the lower proteolysis in myofibrillar protein fraction observed in UV 16 fillets, confirmed by electrophoretic separation. On the other hand, UV treatments decreased collagen content and increased lipid oxidation in fillets. Continuous ultraviolet light is an interesting technology for food preservation due to its ability on the destruction of microorganisms mainly used in fluid and vegetal sanitation but with a proven effect in animal origin food. The advantages of treatment with continuous ultraviolet light for the food industry could be the absence of negative effect on food quality observed with other preservation treatments. The results of the present study showed that UV treatment causes a clear inhibition of microbial growth up to 4-day cold storage, independently of the doses. A consistently higher hardness throughout cold storage and a protective action on myofibrillar protein degradation were also evidenced. Future studies must be performed to minimize the negative effect observed in the present study. • Ultraviolet light was assessed to increase shelf life of sea bass. • UVL treatments decreased microbial counts during the first 4 days post-mortem. • UVL treated fillets showed higher hardness during cold storage. • Lower proteolysis in myofibrillar protein fraction was observed in UV 16 fillets. • UVL treatments decreased collagen content and increased lipid oxidation in fillets.