RT-PCR was known to detect inactivated viruses in water and wastewater (Sobsey et al. 1998) ; the same was likely to be true for inactivated viruses in food. We found that a combination of proteinase K and RNase would eliminate most false-positive RT-PCR results with feline calicivirus (FCV-at that time, the best available surrogate for human norovirus), HAV, and PO1 inactivated by chlorine, heat (72°C), and UV . The treatment did not prevent RT-PCR detection of viruses inactivated at 37°C over long periods of time, as might occur in the environment; although the capsid protected the RNA, it was unable to attach to host cell receptors (Nuanualsuwan and Cliver 2003a) . We compared the infectivity of RNA in PO1 inactivated by chlorine, heat, and UV and found that the rates of inactivation for RNA and whole virus were similar with chlorine and UV inactivation but that RNA infectivity persisted during inactivation at 72°C (Nuanualsuwan and Cliver 2003b) . Several laboratories are now studying other methods to reduce false RT-PCR positive results with inactivated virus (Rodriguez et al. 2009 ).