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Updated: Apr 17, 2026
Alternative In Vitro Methods for the Determination of Viral Capsid Structural Integrity
Published on: November 16, 2017
Efficacy and mechanisms of murine norovirus inhibition by pulsed-light technology
Allison Vimont1, Ismaïl Fliss1, Julie Jean2
1Institute of Nutrition and Functional Foods, Université Laval, Québec, Québec, Canada.
Abstract:
Pulsed light is a nonthermal processing technology recognized by the FDA for killing microorganisms on food surfaces, with cumulative fluences up to 12 J cm(-2). In this study, we investigated its efficacy for inactivating murine norovirus 1 (MNV-1) as a human norovirus surrogate in phosphate-buffered saline, hard water, mineral water, turbid water, and sewage treatment effluent and on food contact surfaces, including high-density polyethylene, polyvinyl chloride, and stainless steel, free or in an alginate matrix. The pulsed-light device emitted a broadband spectrum (200 to 1,000 nm) at a fluence of 0.67 J cm(-2) per pulse, with 2% UV at 8 cm beneath the lamp. Reductions in viral infectivity exceeded 3 log10 in less than 3 s (5 pulses; 3.45 J cm(-2)) in clear suspensions and on clean surfaces, even in the presence of alginate, and in 6 s (11 pulses; 7.60 J cm(-2)) on fouled surfaces except for stainless steel (2.6 log10). The presence of protein or bentonite interfered with viral inactivation. Analysis of the morphology, the viral proteins, and the RNA integrity of treated MNV-1 allowed us to elucidate the mechanisms involved in the antiviral activity of pulsed light. Pulsed light appeared to disrupt MNV-1 structure and degrade viral protein and RNA. The results suggest that pulsed-light technology could provide an effective alternative means of inactivating noroviruses in wastewaters, in clear beverages, in drinking water, or on food-handling surfaces in the presence or absence of biofilms.
Insights
Pulsed light effectively inactivates murine norovirus 1 (MNV-1), a human norovirus surrogate, across various conditions. This nonthermal technology shows promise for disinfecting water and food contact surfaces, even with biofilms.
Area of Science:
- Food Science and Technology
- Microbiology
- Water Treatment
Background:
- Pulsed light (PL) is an FDA-approved nonthermal technology for microbial inactivation on food.
- Human noroviruses are significant foodborne pathogens, necessitating effective inactivation methods.
- Murine norovirus 1 (MNV-1) serves as a reliable surrogate for studying human norovirus inactivation.
Purpose of the Study:
- To evaluate the efficacy of pulsed light for inactivating MNV-1.
- To assess inactivation in diverse aqueous matrices and on food contact surfaces.
- To elucidate the mechanisms underlying pulsed light's antiviral activity.
Main Methods:
- MNV-1 suspensions and surface treatments were exposed to pulsed light (broad spectrum, 200-1000 nm).
- Inactivation was tested in various water types (PBS, hard, mineral, turbid, effluent) and on surfaces (HDPE, PVC, stainless steel).
- Viral structure, protein, and RNA integrity were analyzed post-treatment.
Main Results:
- Over 3 log10 reduction in viral infectivity achieved in <3s on clean surfaces and in clear suspensions.
- Effective inactivation (over 3 log10) observed within 6s on fouled surfaces, except stainless steel.
- Pulsed light disrupted MNV-1 morphology, degraded viral proteins, and damaged RNA.
Conclusions:
- Pulsed light is a highly effective nonthermal technology for inactivating MNV-1.
- It offers a viable alternative for disinfecting wastewaters, beverages, drinking water, and food-handling surfaces.
- Mechanisms involve structural disruption and biomolecular degradation of the virus.
