Bacteria typically starts growing in temperatures 40 degrees and higher. If it stayed in the 30's, it's probably fine.
As far as frothing at the mouth, a symptom of EHD & AHD is foaming at the mouth. The articles below have more information (Google: Deer frothing at the mouth). In all the years I've hunted I've not harvested a deer that foamed at the mouth. I'm not saying this is something you should be concerned about. Just do some research and make your own call. You could call your local warden/game department and ask their advice.
http://www.thesportsmanchannel.com/c.../2012/08/1262/
http://www.dfw.state.or.us/wildlife/...adenovirus.pdf
http://www.taxidermy.net/forum/index.php?topic=285093.0