Norovirus Extraction from Frozen Raspberries Using Magnetic Silica Beads

Human noroviruses (HuNoV) are among the main causes of acute gastroenteritis worldwide. Frozen raspberries have been linked to several HuNoV food-related outbreaks. However, the extraction of HuNoV RNA from frozen raspberries remains challenging. Recovery yields are low, and real-time quantitative reverse transcriptase PCR (RT-qPCR) inhibitors limit the sensitivity of the detection methodologies. A new approach using fine magnetic silica beads was developed for the extraction of HuNoV spiked on frozen raspberries. Relatively low recovery yields were observed with both the magnetic silica bead and the reference ISO 15216-1:2017 methods. High RT-qPCR inhibition was observed with the ISO 15216-1:2017 recommended amplification kit but could be reduced by using an alternative kit. Reducing RT-qPCR inhibition is important to limit the number of inconclusive HuNoV assays thus increasing the capacity to assess the HuNoV prevalence in frozen raspberries.

Automated summary

Human noroviruses (HuNoV) are a major cause of acute gastroenteritis worldwide, and frozen raspberries have been linked to multiple outbreaks. However, extracting HuNoV RNA from frozen raspberries remains challenging, with low recovery yields and inhibition of RT-qPCR limiting detection sensitivity. A new approach using magnetic silica beads showed relatively low recovery yields, highlighting the importance of reducing RT-qPCR inhibition to accurately assess HuNoV prevalence in frozen raspberries.