Thermal Inactivation of Human Norovirus Surrogates

We investigated the thermal inactivation profiles of murine norovirus (MNV), Hepatitis A virus (HAV), and feline calicivirus (FCV), which are surrogates for the study of human noroviruses. Thermal inactivation of MNV and FCV were evaluated at 37, 50, and 60°C and HAV at 37, 50, 60, and 70°C. All viral surrogates were relatively stable at 37°C. MNV and FCV decimal reduction times (D-values) at 50°C were statistically significantly different (P < 0.05) with MNV being more stable. Both surrogates had comparable, low D-values at 60°C. HAV had significantly higher (P < 0.05) D-values than both MNV and FCV at 50 and 60°C. Overall, the infectivity assay results indicate that HAV is resistant to thermal inactivation while MNV is moderately resistant and FCV is least resistant.