Viral RNA Extraction from Raspberries

Viral RNAs were extracted from frozen raspberries using the MSB method as described in Raymond et al. (2021 (link)). Briefly, 40 ml of 150 mM Bis–Tris-Propane buffer pH 8 (Sigma-Aldrich) was used to elute HuNoV from the food matrix (25 g). After elution at pH 8, the eluate was clarified by centrifugation (3500×g for 10 min) and pectinase was added. Magnetic silica fine beads (AccuNanobeads, Bionneer), ascorbic and malic acid (Sigma-Alrich) were then added to the supernatant. The pH was lowered at pH 3 with HCl to maximize virus attachment to the beads. The concentrated virus was eluted by increasing the pH to 7–9. The total RNA was extracted by using the RNeasy Qiacube kit supplemented with DNase 1 as recommended by the manufacturer (QIAGEN).