Foodborne outbreaks associated with transmission of norovirus are increasingly becoming a public health concern. Foods can be contaminated with faecal material at the point of production or during food preparation, in both the home and in commercial premises. Transmission of norovirus occurs through the faecal-oral route, either via person-to-person contact or through faecal-contamination of food, water, or environmental surfaces. Understanding the role and pathways of norovirus transmission – either via food handlers' hands, contaminated foods or the environment – remains a key public health priority to reduce the burden of norovirus-associated gastroenteritis. However the proportion of norovirus that is typically transferred remains unknown. Understanding this is necessary to estimate the risk of infection and the burden of gastroenteritis caused by norovirus. In this paper we present a novel method of capture, concentration and molecular detection of norovirus from a wider range of complex food matrices than those demonstrated in existing published methods. We demonstrate that this method can be used as a tool to detect and quantify norovirus from naturally contaminated food, and for monitoring norovirus transfer between food handlers' gloved hands, food or the environment. We measure the effect of introducing contamination at different food production process stages, to the final food product, to determine whether this could cause infection and disease. Between 5.9 and 6.3 Log10 cDNA copies/μl of norovirus GII were inoculated onto food handlers' gloved hands, food or the environment and 1.1–7.4% of norovirus contamination was recovered from all samples tested. When interpreted quantitatively, this percentage equates to levels predicted to be sufficient to cause infection and disease through consumption of the final food product, demonstrating a public health risk. Overall detection and quantification of norovirus from foods, food handlers' gloved hands and the environment, when suspected to be implicated in foodborne transmissions, is paramount for appropriate outbreak investigation.
Bibliographical noteFunding Information: We have no conflicts of interest to disclose. The research was funded as part of a PhD studentship by Public Health England, to establish a method for detecting viruses from foods. This work was funded as a Public Health England PhD studentship and London School of Hygiene and Tropical Medicine.
Open Access: This is an open access article under the CC BY-NC-ND license
Publisher Copyright: Crown Copyright © 2021 Published by Elsevier B.V.
Citation: Derrick, Jade, et al. "Measuring transfer of human norovirus during sandwich production: Simulating the role of food, food handlers and the environment." International Journal of Food Microbiology (2021): 109151.
- Environmental virology
- Foodborne virus
- Public health
- Virus detection