#echo 0 > authorized
To ENABLE the USB port...
#echo 1 > authorized
appears to successfully toggle it back ON/Enabled...also, disabling USB access by the method above appears to NOT persist through a reboot so this likely would need to be part of a script run by your app or part of your app if you need to maintain a disabled port for the sake of security
USB Disable/Enable method described here also appears to work on USB mass storage (thumb drive) - i.e. when disabled, the "udisk" folder shows up empty in ESFileExplorer
This has only been proven in concept by trying from a shell session.