It depends on the context. "I have not" COULD mean "I have never", OR it could mean that you "have not" in this particular case. "I have never" means not at any point previous. "I have not" COULD only mean you haven't at this particular time.

We would never say "I have not eaten this food." It is incomplete in meaning; it needs a time element. 1. I have never eaten this food before. 2. I haven't eaten this dish before. (same meaning as #1; #1 is more correct in this context)

'never' means to not have the intention 'not' mean to have the intention