Inactivation of a Foodborne Norovirus Outbreak Strain with Nonthermal Atmospheric Pressure Plasma

Abstract

Human norovirus (NoV) is the most frequent cause of epidemic nonbacterial acute gastroenteritis worldwide. We investigated the impact of nonthermal or cold atmospheric pressure plasma (CAPP) on the inactivation of a clinical human outbreak NoV, GII.4. Three different dilutions of a NoV-positive stool sample were prepared and subsequently treated with CAPP for various lengths of time, up to 15 min. NoV viral loads were quantified by quantitative real-time reverse transcription PCR (RT-qPCR). Increased CAPP treatment time led to increased NoV reduction; samples treated for the longest time had the lowest viral load. From the initial starting quantity of 2.36 × 104 genomic equivalents/ml, sample exposure to CAPP reduced this value by 1.23 log10 and 1.69 log10 genomic equivalents/ml after 10 and 15 min, respectively (P < 0.01). CAPP treatment of surfaces carrying a lower viral load reduced NoV by at least 1 log10 after CAPP exposure for 2 min (P < 0.05) and 1 min (P < 0.05), respectively. Our results suggest that NoV can be inactivated by CAPP treatment. The lack of cell culture assays prevents our ability to estimate infectivity. It is possible that some detectable, intact virus particles were rendered noninfectious. We conclude that CAPP treatment of surfaces may be a useful strategy to reduce the risk of NoV transmission in crowded environments.Importance Human gastroenteritis is most frequently caused by noroviruses, which are spread person to person and via surfaces, often in facilities with crowds of people. Disinfection of surfaces that come into contact with infected humans is critical for the prevention of cross-contamination and further transmission of the virus. However, effective disinfection cannot be done easily in mass catering environments or health care facilities. We evaluated the efficacy of cold atmospheric pressure plasma, an innovative airborne disinfection method, on surfaces inoculated with norovirus. We used a clinically relevant strain of norovirus from an outbreak in Germany. Cold plasma was able to inactivate the virus on the tested surfaces, suggesting that this method could be used for continuous disinfection of contaminated surfaces. The use of a clinical strain of norovirus strengthens the reliability of our results as it is a strain relevant to outbreaks in humans.

Inactivation of murine norovirus-1 and hepatitis A virus on fresh meats by atmospheric pressure plasma jets

“…It has been reported that several factors can influence the inhibitory effects, such as microbial species, exposure type, injected gas type, and the number of cell layers in the sample . The plasma emits antiviral and antimicrobial materials, such as photons, electrons, positive and negative ions, free radicals, neutral atoms, UV photons, as well as reactive oxygen and reactive nitrogen species, with enough energy to affect the foodborne pathogens (Wan et al, 2009;Ahlfeld et al, 2015). During the exposure to the plasma, these particles have a sterilization effect by directly being in contact with the surface.…”

“…Plasma consists of photons, electrons, positive and negative ions, free radicals, neutral atoms, UV photons, reactive oxygen (ozone, atomic oxygen and singlet oxygen) and reactive nitrogen species (NO radicals,NO 2 ,NO 3 , N 2 O 3 , N 2 O 4 and ONOO¯) (Ahlfeld et al, 2015;Gweon et al, 2010;Wan, Coventry, Swiergon, Sanguansri, & Versteeg, 2009). Various active species and UV photons were inactivating the virus particles, bacteria, fungi and yeast by destroying the genetic material (Ahlfeld et al, 2015;Fridman et al, 2007;Moisan et al, 2001Moisan et al, , 2002. In addition, the beginning of the exposure to the APP, these elements generate a synergistic effect (Ahlfeld et al, 2015).…”

“…Various active species and UV photons were inactivating the virus particles, bacteria, fungi and yeast by destroying the genetic material (Ahlfeld et al, 2015;Fridman et al, 2007;Moisan et al, 2001Moisan et al, , 2002. In addition, the beginning of the exposure to the APP, these elements generate a synergistic effect (Ahlfeld et al, 2015).…”

“…Furthermore, Noriega, Shama, Laca, Diaz, and Kong (2011) and Rød et al (2012) demonstrated the impact of APP inactivation on chicken meat and ready-to-eat meat (bresaola) targeting Listeria innocua. Also, the influence of APP on NoV strain was described by Ahlfeld et al (2015). However, studies of the effects of APP on virucidal contaminated with foods are not enough relatively.…”

An Atmospheric Pressure Plasma Setup to Investigate the Reactive Species Formation

“…These species, initially generated in the gas phase, are further delivered by the plasma to the biological substrate 5 . RONS interact with substrates and thus define the antimicrobial, anticancer and antiviral effects of LTP [6][7][8] .…”