Noroviruses in food chain production

Abstract

Viruses, predominantly noroviruses, are progressively identified as the leading cause of foodborne diseases worldwide. In the Europe Union they have been determined as a main cause of foodborne outbreaks in 2014, while in the United States viruses are responsible for 58% (5.5 million) of foodborne illnesses annually. Noroviruses, the etiological agent of foodborne gastroenteritis belong to the Caliciviridae family, genus Norovirus which is genetically classified into 6 established geno-groups (GI to GVI). Human noroviruses are icosahedral nonenveloped RNA viruses, approximately 27 to 38 nm in diameter, and contain single-stranded positive-sense RNA genomes size from 7.4 to 8.3 kb and 3 open reading frames. Viruses are transmitted by contaminated food or water, through person-to-person contact, and by cross-contamination from surfaces. Foods at risk includes those which need extensive handling, mostly ready-to-eat foods that do not undergo further processing, and those exposed to environmental contamination, such as seafood and fresh produce. Contamination with human norovirus can happen throughout the entire food production chain: (i) at the primary production (due to fecal polluted water in the harvest area/ irrigation/ water used to dilute pesticide, organic-based fertilizers and potential root uptake of pathogens following internalization); (ii) during harvest (contact with human feces or fecal soiled materials, cross-contamination with equipment and food handlers poor hygiene practice); (iii) at the post-harvest stage by inappropriate practices during handling, processing, preparation, storage, distribution (by infected food handlers, spraying with contaminated water, cross-contamination during washing process) and (iv) at the point of sale/consumption (by infected food handlers, cross-contamination with polluted working instruments or surfaces previously contaminated by infected food handlers or food items). Strategies to reduce human noroviruses in the food chain should, beside good hygiene practice, engage interventions to prevent their adsorption to food/contact surfaces and inactivation on/within the products using successful processing techniques.