Potential sources of error during virus thermal inactivation

A review of virus thermal inactivation data published in the literature demonstrated variations in reported virus resistance. Examination of the methods used indicated that numerous studies were made by heat processing virus suspensions in test tubes. Duplication of some of the methods using milk suspensions of poliovirus 1 showed virus persistence after heating as a result of uneven temperature distribution inside the test tubes. Unless the containers (preferably sealed ampoules or capillary tubes) are completely submerged in the water bath and agitated vigorously, apparent virus persistence may be encountered.