Many animal viruses can be stored by flash freeze the virus-containing
supernatant in a dry-ice bath or liquid nitrogen, and stored at -70 °C
or in liquid nitrogen.
Viruses in supernatant or tissues can also be preserved by freeze-dry and
stored at -70 °C or in liquid nitrogen.
To recover frozen viruses, thaw quickly in 37 °C. Avoid repeated freeze-and-thaw,
some viruses can only be thawed once without destroying infectivity.