Norovirus Inactivation Using Chlorine Dioxide Gas on Stainless Steel Coupons

Introduction:   Acute gastroenteritis caused by human norovirus is becoming a significant public health issue. Fresh produce and seafood are examples of high risks foods associated with norovirus outbreaks. Chlorine disinfectant, at the dosage recommended by the Food and Drug Administration, is not effective in norovirus inactivation. Previous studies have shown that chlorine dioxide gas is an effective antimicrobial agent for different pathogenic bacteria on fresh produce. 

Purpose:   The objective of this study was to determine the effectiveness of chlorine dioxide gas to inactivate norovirus on stainless steel coupons that could mimic food contact surfaces in the food industry. 

Methods:   The cultivable murine norovirus (MNV-1) was used as a surrogate for human norovirus and was inoculated on stainless steel coupons at the concentration of 10⁸PFU/ml. The samples were treated with chlorine dioxide gas at 1 mg/l and 8 mg/l for 1, 5, and 15 min at 25°C. Viral plaque assays were used for quantification of recovered viral particles. 

Results:   At a concentration of 1 mg/l, there was approximately a 1.5-log reduction in MNV-1 particles after treating the stainless steel coupons for 15 min. At the higher concentration (8 mg/l), no plaques could be found after treatment of 1, 5, or 15 min which resulted in a > 5-log reduction in MNV-1 particles.

Significance:   Chlorine dioxide gas at 8 mg/l effectively inactivates human norovirus surrogate. This treatment method yields promising results for potential use on food contact surfaces and possible for food surfaces.  More research should be completed to better understand inactivation kinetics for norovirus in high risk foods (such as fresh produce and seafood) in an effort to reduce the incidence of norovirus-related outbreaks.