Inactivating treatments for viruses such as pasteurization or alkylation by beta-propiolactone or binary ethyleneimine were tested for their capacity to modify nucleic acids. The modification of a nucleic acid was measured as the decrease in spot intensity in Southern blots after polymerase chain reaction (PCR) amplification. The inactivating treatments were applied to cellular and viral genomic material from a human lymphoblastoid cell line immortalized by Epstein Barr Virus (EBV), which produced a monoclonal antibody. Pasteurization did not modify the ability to amplify and detect cellular or viral DNA. Binary ethyleneimine strongly reduced the amount of detectable DNA and beta-propiolactone under particular conditions of incubation abolished all trace of DNA.