Edit the registry key for the quarantine release email in order to change the email output.
Using the Registry Editor:
Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry be made prior to making any registry changes.
After taking these steps, quarantine release emails will now have the "QuarantineReleasedSubjectStr" value as the message subject, and the "QuarantineReleasedBodyStr" as the message body.