Persistence of norovirus in static and dynamic simulators of the human gastrointestinal tract

Human norovirus (HuNoV), transmitted via the fecal-oral route, is a major cause of gastroenteritis worldwide. However, its persistence during gastrointestinal digestion, particularly in the presence of high-risk food matrices, remains poorly understood. The aim of this study was to evaluate the persistence of HuNoV and murine norovirus 1 (MNV-1) during simulated gastrointestinal digestion using two complementary in vitro models: the standardized static INFOGEST protocol and the dynamic TIM-1 simulator. Viruses were suspended in water or mixed with puréed raspberries, strawberries, lettuce, or oysters. MNV-1 infectivity was quantified by plaque assays, complemented by PMAxx RT-qPCR, while HuNoV persistence was assessed exclusively by PMAxx-RT-qPCR as a proxy for potentially intact viral particles. Under static digestion conditions, MNV-1 titer decreased by approximately one log PFU/mL during the gastric phase in the presence of raspberry purée with a similar reduction observed for HuNoV RNA. In contrast, during dynamic digestion in TIM-1 system, both viruses persisted throughout all gastrointestinal compartments, regardless of the food matrix tested. These results highlight the persistence of noroviruses during gastrointestinal transit and reinforce the importance of preventive control measures for high-risk foods.