Fruitfly infestation

[Evan Sage]

Within the last two weeks or so, fruitflies (I assume) have appeared in 
our house, mostly in the kitchen but no room is unaffected, and they seem 
to be multiplying. I have removed all obvious sources of food - bowls of 
fruit, etc. This doesn't seem to have helped.
 
Any suggestions on how to treat (what spray would I buy in an ordinary 
store, etc.)
 
Thanks in advance!
 
   Evan Sage