If your concerned about the content of the swap partition you can always turn it off as specified in the usual way with
sudo swapoff -a and then fill the swap partition with zeros or random data using dd.
First find your swap partition use Disks, Disk Utility, gparted (GUI) or the content of fstab to find it (
Having located it and double and triple checked it's location at say sda5 or some such issue the "disk destroyer" command (not to be used lightly)
sudo dd if=/dev/zero of=/dev/sda5
to blast it full of zeros or
sudo dd if=/dev/random of=/dev/sda5
to blast it full of random data.
The next time you turn swap on with
The system will happily use it again. If you have plenty of RAM you may not need swap at all. Issue the command
when the system is under heavy load and see how much is in use to make this determination.