See if you can fix the gap somehow.
Try putting a small piece of fruit in all of you're vivs, to try and lure the ff's into staying put.
Take a wine or beer bottle(s) with a little left in, add a drop of dish soap, and some water and shake, put these where the ff's tend to gather(outside the viv) the detergent breaks the surface tension of the water and the ff's, lured by the yeast in the libation, drown in the mixture.
As pastor josh said, put you're fruit in the fridge.
Take you're kitchen garbage outside everyday.
Do you're dishes just as often...even if this doesn't improve the fly situation, you're housemates will like you better!
Do all of this, and you should see improvement in a week, if not, maybee you are feeding way too much.