Survival and Inactivation by Advanced Oxidative Process of Foodborne Viruses in Model Low-Moisture Foods

Abstract

16Enteric viruses, such as human norovirus (NoV) and hepatitis A virus (HAV), are the major 17 causes of foodborne illnesses worldwide. These viruses are shed in high numbers, have low 18 infectious dose, and may remain infectious for weeks in the environment and food. While 19 numerous viral survival studies have been conducted in fresh fruits and produce, limited 20 information is available regarding viral survival and transmission in low moisture foods (LMF). 21 LMFs are generally considered as ready-to-eat products, which undergo no or minimal pathogen 22 reduction steps. However, numerous foodborne outbreaks associated with LMFs have been 23 reported in recent years. The objective of this study was to examine the survival of foodborne 24 viruses in LMFs during long-term storage at ambient temperature and to evaluate the efficacy of 25 advanced oxidative process (AOP) treatment in the inactivation of these viruses. For this 26 purpose, select LMFs such as pistachios, chocolate, and cereal were inoculated with HAV and 27 the norovirus surrogates, murine norovirus (MNV) and feline calicivirus (FCV), then viral 28 survival on these food matrices was measured over a four-week incubation at ambient 29 temperature, by both plaque assay and droplet-digital RT-PCR (ddRT-PCR). We observed an 30 approximately 0.5 log reduction in viral genome copies, and 1 log reduction in viral infectivity 31 for all three tested viruses following storage of select inoculated LMFs for 4 weeks. Therefore, 32 the present study shows that foodborne viruses can persist for long-time in LMFs. Next, we 33 examined the inactivation efficacy of AOP treatment, which combines UV-C, ozone, and 34 hydrogen peroxide vapor, and observed that while approximately 100% inactivation can be 35 achieved for FCV, MNV, and HAV in chocolate, the inactivation efficiency diminishes to 36 approximately 90% in pistachios and 70% in cereal. AOP treatment could therefore be a good 37 candidate for the elimination of foodborne viruses from certain LMFs depending on the food 38 matrix and surface of treatment. 39 Importance 40 Low moisture foods have been increasingly recognized as important vehicles of foodborne 41 pathogens. In the present study, we demonstrated that foodborne viruses remain infectious during 42 long-term storage on select low moisture foods. In addition, we evaluated the efficacy of an 43 advanced oxidative process in the inactivation of foodborne viruses in low moisture foods. This 44 research will help increase the safety of low moisture foods and reduce the number of foodborne 45 illnesses due to contaminated products. 46 Keywords: Hepatitis A virus, norovirus surrogates, low moisture foods, bead-based assay, 47 whole genome sequencing, advanced oxidative process 48 49 50 51 Gastroenteritis outbreaks and illnesses due to the consumption of contaminated low moisture 52 foods (LMFs) are recently emerging as food safety burden in developed countries, with 53 norovirus and hepatitis A virus being important causes of LMF-associated outbreaks...