If anything, I think the music professor you spoke to is more than a bit misinformed, that the likelyhood is that most composition departments lean towards what you call avant garde composition, whether it is 12 tone/serialism, atonality in its many forms, or minimalism. That is a broad overview, and it depends on the school and program, there is fortunately a lot less rigidity than when people like Babbitt and the like were running around promoting the new orthodoxy or whatever you want to call it.
I agree with what others have written, one way is to search schools websites for student pieces that have been performed, if they all see to be only one style or similar styles, that might be an indication of the department. Likewise, check out the pieces the faculty as written, and see what you see.