Previous bacterial infection affects textural quality parameters of heat-treated fillets from rainbow trout (Oncorhynchus mykiss)

Sensory quality of fish meat is influenced by many parameters prior to slaughter. In the present study, it was examined if previous infections or damages in the muscle tissue influence product quality parameters in fish. Fillets from rainbow trout (Oncorhynchus mykiss) reared in seawater at a commercial fish farm were sensory evaluated for more than a year after recovery following physical tissue damage or infection by the bacterial pathogens Yersinia ruckeri and Vibrio anguillarum. The effect of vaccination was also included as some fish were vaccinated before bacterial challenge. The fish fillets were sensory examined as heat-treated and cold-smoked. Heat-treated fillets from nonvaccinated fish previously infected by V. anguillarum had changed textural characteristics and were less flaky, had a lower oiliness and a higher toughness and fibrousness in comparison with control fish. This article was the first to describe a correlation between previous infections in fish and changes in sensory-quality parameters. PRACTICAL APPLICATIONS. This work contributes with knowledge about sensory-quality parameters of fish meat after recovery from infections and physical-tissue damage. Because the results demonstrate an influence on the texture from previous disease, the practical potentials of the results are valuable for the aquaculture industry. In order to minimize the effects of previous diseases on the sensory quality regarding the texture, these fishes should be processed as cold-smoked instead of being sold as raw meat. The established correlation between disease history stresses the importance of disease prevention in aquaculture production, e.g., vaccination of the fish.