Efficacy of commercial curing processes for treatment of quarantinable disease-causing pathogens in salmon roe

Abstract

The distribution of salmon roe poses a risk to the salmon industry due to the potential transmission of quarantinable disease-causing pathogens. The curing of commercial salmon roe with saturated saline or soy sauce seasoning is widespread in Japan. The aim of this study was to evaluate the effect of commercial curing processes on quarantinable disease-causing pathogens [Aeromonas salmonicida, Renibacterium salmoninarum, Yersinia ruckeri, infectious hematopoietic necrosis virus (IHNV), infectious pancreatic necrosis virus (IPNV), Oncorhynchus masou virus (OMV)] of salmon. Curing with saturated saline for 8 min slightly decreased the viability of A. salmonicida, from 6.0 log colony-forming units (CFU)/ml to 5.1 log CFU/ml, but did not affect the viability of R. salmoninarum or Y. ruckeri. Curing with soy sauce seasoning for 90 min decreased the viability of A. salmonicida from 5.5 log CFU/ml to undetectable levels, but did not affect those of R. salmoninarum or Y. ruckeri. Neither saturated saline nor soy sauce seasoning affected the infectivity of IHNV, IPNV or OMV. In conclusion, the efficacy of curing was only demonstrated for A. salmonicida when soy seasoning was employed. This study shows that quarantine measures other than those examined here need to be developed for the safe distribution of salmon roe.