For products to be used below 40 °C, the DVV or EN method provides for test viruses that are not thermostable, i.e., they are inactivated to some extent at higher temperatures simply due to the temperature. If products to be used at above 40 °C were tested with the same test viruses, the overall effect would be partly due to the high temperature and partly to the disinfectant. Therefore, the effect of the product can no longer be measured reliably with these viruses alone. The parvovirus is thermostable; thus, it serves as a reference virus to determine effective use concentrations of the disinfectant even at higher temperatures.
