Efficacy and Mechanisms of Murine Norovirus Inhibition by Pulsed-Light Technology

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 log 10 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 log 10 ). 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.H uman noroviruses are responsible for one-fifth of all cases of acute gastroenteritis worldwide (1). They spread directly via person-to-person contact (fecal-oral and vomitus-oral) or indirectly through food, water, and the environment (2). Natural biofilms in sewage treatment effluent could be responsible for many persistent waterborne outbreaks, since such biofilms have been found to harbor noroviruses (3, 4). Infection spreads quickly and widely, affecting individuals of all ages, especially where many people gather or live in close proximity, such as in long-term care residences, retirement homes, cruise ships, and the like. Infectious doses as low as 2,800 particles, the high viral loads in feces and vomit (up to 10 9 genomic copies per gram), persistence in the environment, prolonged duration of viral shedding even after symptoms have resolved, and inadequate long-term immunity all contribute to the high incidence of norovirus illness (5). Although the illness is usually mild and self-limiting, the large number of cases per year represents a considerable loss in productivity and constitutes a substantial burden on society (2, 6).Among the physical disinfection processes, pulsed-light treatment appears well suited for the disinfection of food contact surfaces in industrial and health care settings and for decontaminating water and beverages. It has been proposed as a means of nonthermal pasteurization for food preservation and for decontaminating air and packaging materials (7). It has proven effective for inactivati...

In Vitro Antiviral Activity of Clove and Ginger Aqueous Extracts against Feline Calicivirus, a Surrogate for Human Norovirus

“…Therefore, the development of novel nonthermal technologies for viral decontamination of foods is of great interest to food scientists and food producers. A few studies are available on the virucidal effects of such technologies to combat foodborne viral contamination, e.g., ozone treatment (20), gamma irradiation (17), lactic acid bacteria used as an antiviral biopreservative (1), pulsed-light technology (38), and, most recently, cold atmospheric pressure gaseous plasma (2). Another growing trend of investigation is the exploration of natural compounds for their antiviral properties.…”

Recent findings in pulsed light disinfection

“…In case of murine norovirus, Vimont et al . () also found that PL disrupts MNV‐1 structure and degrades viral proteins and RNA. On the other hand, Nicorescu et al .…”

“…Viruses like murine norovirus as a surrogate for human norovirus have also been proven to be sensitive to PL exposure in different matrices, reaching reductions of viral infectivity by more than 3 log units with 3·45–7·6 J cm −2 (Vimont et al . ). A range of viruses like herpes simplex virus type 1 and nonenveloped viruses, that is, encephalomyocarditis, polio virus type 1, hepatitis A (HAV), bovine parvovirus and canine parvovirus have been shown to be PL sensitive, revealing inactivation of >4·8–>7·8 log with 1 J cm −2 (Roberts and Hope ).…”

Foodborne viruses: Detection, risk assessment, and control options in food processing

“…The mechanism involved in antiviral activity of PL is probably disruption of viral structure that ultimately degrades viral proteins and RNA. PL at 12 J/cm 2 with 3-6 s exposure resulted in > 3.0 log 10 reduction of MNV in various liquids (Vimont et al, 2015). PL or UV may be used in combination with other control strategies (e.g.…”