Fig. 4

Effect of 100 °C heating on IAV (PR8 strain) infectivity and copy numbers. IAV suspensions were heated with a block incubator for increasing periods of time between 1 and 5 min. IAV infectivity was measured by TCID₅₀ assay using MDCK cells. The copy numbers were measured using LR-RT-qPCR targeting the PA segment. The titers are plotted on the graph and shown as log (TCID₅₀/0.1 mL) (◆). Assays were performed independently three times with quadruplicate wells per dilution and values represent the mean ± standard error. No CPE was observed after 1 min of heating, and these were defined as 0 (means ‘not detected’) for convenience. The ratios of copy numbers obtained using LR-RT-qPCR and conventional RT-qPCR are also plotted on the graph (● and ▲), respectively. Assays were carried out independently three times with three different lots of the PR8 stocks and plots represent the mean ± standard error and individual values. A broken line indicated the LoD of LR-RT-qPCR. The data indicated in Additional Table 4 (See ‘Additional Tables’)