Inactivation of murine norovirus-1 and hepatitis A virus in the Korean traditional preserved raw crab product Ganjanggejang by soy sauce during storage

Abstract

Enteric norovirus (NV) and hepatitis A virus (HAV) are the major causes of nonbacterial foodborne gastroenteritis. This study examined the effects of soy sauce containing different concentrations of NaCl (5, 10, 15, and 20%) on the survival of murine norovirus-1 (MNV-1), which was used as a human NV surrogate, and HAV in experimentally contaminated raw crabs during 5 d of storage at 10 °C. Both MNV-1 and HAV titers and decimal reduction times (D-values) significantly (P < 0.05) decreased with stepwise increases in the NaCl concentration of soy sauce and storage time. The overall reductions in MNV-1 and HAV titers in Ganjanggejang marinated in soy sauce containing 20%, 15%, 10%, and 5% NaCl were 0.98 and 1.09, 0.81 and 0.88, 0.58 and 0.71, and 0.31 and 0.45 log10 50% tissue culture infective dose (TCID50)/mL, respectively. MNV-1 and HAV titers were not reduced >90% in Ganjanggejang marinated in soy sauce containing 5% NaCl, even after the maximum storage period (5 d). Using the first-order reaction model (R2 was >0.95), we determined that the D-values for MNV-1 and HAV were 2.96 and 2.65 d, 3.39 and 3.29 d, 4.68 and 4.03 d, and 8.18 and 5.51 d in Ganjanggejang marinated in soy sauce containing 20%, 15%, 10%, and 5% NaCl, respectively. Our results suggest that soy sauce containing higher concentrations of NaCl (>20% NaCl) or 10–20% NaCl with longer storage times (>5 days of storage) could have a more complete inactivation (3 log-reduction) of both MNV-1 and HAV in conventional Ganjanggejang.