If you've tried the usual hints, and thy obviously haven't worked, and she is as direct as you say, then bite the bullet and tell her straight.
Get her on her own, tell her you'd like a word, and then just tell her that her hygene is a talking point, and you;re sure she'd rather know than be talked about, and you know she'll be keen to address the issue now she is aware - then beat it!
The embarasment is only going to be brief, compared with weeks and months of this unpleasant situation, so I'd just go for it. She's a professional adult - she must learn to accept being addressed as one.