Erm, just grep for the pattern and invert the sense of exit code (if grep exits successfully (the file does contain the pattern at least once) then you don't want that file; if it exits with an error you do want it (since it didn't contain the pattern at all)).

Update: Actually if you have GNU grep (i.e. don't know if this is a kosher POSIX grep option) just use the -L flag:

  -L, --files-without-match only print FILE names containing no match
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