If you have like Maxx Air covers over your vent's I would leave the vents open,
I leave my vents open all the time since I have Maxx Air II covers over mine. This allows the off gassing even though my trailer never had this problem.
after each trip I clean my fridge and use something to keep it open so it doesnt get mold or mildew which so far has worked great.
2011 Rockwood Mini Lite 2306 - Matt
2004 Dodge Ram 1500 Qaud Cab 4x4 with 35" tires and 3.92 gears, Dynatech Longtube Headers & Fabtech 6" lift + Superchips with shift Tuning
Nights Camped 2011 (37) - 2012 (16)-2013 (2) -2014 (5) -2015(0)
USMC 91 - 95 - F/A-18 Aviation Ordnance