Ultraviolet-C efficacy against a norovirus surrogate and hepatitis A virus on a stainless steel surface

• MNV-1 reductions on stainless steel surfaces by 10–300 mWs/cm2 UV-C were 0.0–4.3 log10PFU/ml.
• HAV reductions on stainless steel surfaces by 10–300 mWs/cm2 UV-C were 0.0–2.6 log10PFU/ml.
• dR-value for MNV-1 was 33.3 mWs/cm2 UV-C.
• dR-value for HAV was 55.4 mWs/cm2 UV-C.
• Low doses of UV-C light were effective to inactivate human NoV and HAV on food contact surfaces.

In this study, the effects of 10–300 mWs/cm2 of ultraviolet radiation (UV-C) at 260 nm were investigated for the inactivation of two foodborne viruses: murine norovirus-1 (MNV-1; a human norovirus [NoV] surrogate) and hepatitis A virus (HAV). We used an experimentally contaminated stainless steel surface, a common food-contact surface, to examine the effects of low doses of UV-C radiation on MNV-1 and HAV titers. The modified Gompertz equation was used to generate non-linear survival curves and calculate dR-values as the UV-C dose of 90% reduction for MNV-1 (R2 = 0.95, RMSE = 0.038) and HAV (R2 = 0.97, RMSE = 0.016). Total MNV-1 and HAV titers significantly decreased (p < 0.05) with higher doses of UV-C. MNV-1 and HAV were reduced to 0.0–4.4 and 0.0–2.6 log10PFU/ml, respectively, on the stainless steel surfaces by low-dose UV-C treatment. The dR-value, 33.3 mWs/cm2 for MNV-1 was significantly (p < 0.05) lower than 55.4 mWs/cm2 of HAV. Therefore, the present study shows that HAV is more resistant to UV-C radiation than MNV-1. These data suggest that low doses of UV-C light on food contact surfaces could be effective to inactivate human NoV and HAV in restaurant, institutional, and industrial kitchens and facilities.