Virucidal Effect of Cold Atmospheric Gaseous Plasma on Feline Calicivirus, a Surrogate for Human Norovirus

Abstract

Minimal food-processing methods are not effective against foodborne viruses, such as human norovirus (NV). It is important, therefore, to explore novel nonthermal technologies for decontamination of foods eaten fresh, minimally processed and ready-to-eat foods, and food contact surfaces. We studied the in vitro virucidal activity of cold atmospheric gaseous plasma (CGP) against feline calicivirus (FCV), a surrogate of NV. Factors affecting the virucidal activity of CGP (a socalled radio frequency atmospheric pressure plasma jet) were the plasma generation power, the exposure time and distance, the plasma feed gas mixture, and the virus suspension medium. Exposure to 2.5-W argon (Ar) plasma caused a 5.55 log 10 unit reduction in the FCV titer within 120 s. The reduction in the virus titer increased with increasing exposure time and decreasing exposure distance. Of the four plasma gas mixtures studied (Ar, Ar plus 1% O 2 , Ar plus 1% dry air, and Ar plus 0.27% water), Ar plus 1% O 2 plasma treatment had the highest virucidal effect: more than 6.0 log 10 units of the virus after 15 s of exposure. The lowest virus reduction was observed with Ar plus 0.27% water plasma treatment (5 log 10 unit reduction after 120 s). The highest reduction in titer was observed when the virus was suspended in distilled water. Changes in temperature and pH and formation of H 2 O 2 were not responsible for the virucidal effect of plasma. The oxidation of viral capsid proteins by plasma-produced reactive oxygen and nitrogen species in the solution was thought to be responsible for the virucidal effect. In conclusion, CGP exhibits virucidal activity in vitro and has the potential to combat viral contamination in foods and on food preparation surfaces. Foodborne illnesses continue to plague public health, as well as world economies, costing approximately $152 billion in the United States alone (1). Enteric viruses, particularly human norovirus (NV) and hepatitis A virus (HAV), are the leading causes of viral foodborne illnesses (2). Human NV, one of the top five pathogens with respect to the total cost of foodborne illnesses in the United States, belongs to the family Caliciviridae and is a wellknown cause of "winter vomiting disease" or "stomach flu" (3). NV causes 19 to 21 million cases of acute gastroenteritis annually in the United States and leads to 1.7 to 1.9 million outpatient visits, 400,000 emergency room visits, 56,000 to 71,000 hospitalizations, and 570 to 800 deaths, mostly among young children (4). More than half of all foodborne disease outbreaks due to a known cause reported to the CDC from 2006 to 2010 were attributed to NV. In the European Union in 2007, caliciviruses (primarily NV) were responsible for 507 of 675 foodborne viral disease outbreaks (5).Multiple issues related to the quality of thermally processed foods, e.g., nutritional losses and adverse effects on organoleptic quality, have led to the emergence of so-called nonthermal technologies, which consist of preservation treatments that are effective at ambient o...

New Proof-of-Concept in Viral Inactivation: Virucidal Efficacy of 405 nm Light Against Feline Calicivirus as a Model for Norovirus Decontamination

“…Similarly, studies investigating the virucidal effects of UV-light, ozone, hydrogen peroxide vapour and cold atmospheric gas plasma technologies have also used FCV as a NoV surrogate (Nuswalen et al 2002; Hudson et al 2007; Bentley et al 2012; Aboubaktar et al 2015; Holmdahl et al 2016). …”

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

“…The expected mode of action of the antiviral activity of the natural extracts is the chemical interaction between the bioactive chemical compounds of the extracts and the virus or its hosting cells. Therefore, as a worst-case scenario, we selected FCV in our study because it is known to have higher resistance to chemical disinfectants as compared to the other NoV surrogates, such as murine norovirus (2,5,6,33,34). The plant materials were chosen from among those that are consumed commonly as constituents of food, such as fresh vegetable salads.…”

“…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.…”

Effect of Leaf Surface Chemical Properties on Efficacy of Sanitizer for Rotavirus Inactivation

“…However, chlorine is consumed by the organic matter that is present on produce, which may result in unstable disinfection efficacy (28). These shortcomings motivate the development of alternative sanitation methods using non-chlorine-based sanitizers (29)(30)(31), ozone (24,32), ultrasound (33,34), heat (35,36), cold atmospheric gaseous plasma (26), and electron beams (37). However, it remains unclear how nonchlorine chemical sanitizers inactivate viruses on fresh produce.…”

“…The current sanitation treatments employed in the food industry may not effectively inactivate viruses that have adsorbed to fresh vegetables (24)(25)(26)(27). Chlorine-based sanitizers are the most commonly used sanitizers in the food industry.…”