Savage Worlds is pretty good about making game terms stand out with various font alterations. Contact has no such alteration, and isn't defined anywhere else in the rules, therefore it is using the common English definitions.
Contact noun - the state or condition of physical touching.
Poking it with a stick, even a sharp metal stick like a sword, isn't contact. Poking it with your finger, nose, foot, or other body part would be contact.
Using someone else's body part, severed or not, would be contact for that body part but probably not for you.
Obviously, the GM has final say on what is or isn't "contact" for a damaging barrier.