You have to be careful with Quat, it will destroy your equipment if not properly mixed.
I use bleach at 1 to 4 ratio but my requirements are to ensure that the equipment is properly dried after applied. As soon as I can, i'm going to a pre-mix station and using a quat based sanitizer.
Additionally, I start with a heavy degreaser (simple green crystal) with no odor and colorless. Then I finish with my sanitizer.
I've have not had any positive listeria test or any issues with mold, yeast or apc.
FYI, I'm a blown film manufacturer with winders, bag machines, extruders.