Help! I'm petrified! I have never had a roach in my home, ever, in fact I sanitize counters, mop and vacuum floors constantly, yet this morning there was a huge (an inch or so) tan roach sitting on my sink. I absolutely freaked out. It's dead. Then I read up online and tried to identify it,seems to me it might be a German roach, so I immediately went to the store, bought boric acid and some Ortho spray and combat roach baits, sprinkled the boric along the foundation outside the house, along inside and outside of windows, doorways, basement windows and cracks and crevices in my kitchen.
Contrary to popular opinion, roaches do get in clean houses! You can, as you stated, get them from grocery bags (usually the really small ones) or from trees around your house (usually large ones). I have found that Bengal Roach Spray is the best on the market for controlling them. It not only lasts a long time but has no odor to aggravate any allergies you or any of your family may have. It costs more, but it's definitely worth it.
Many years ago when my mother was unpacking her groceries, she saw a roach crawl out of a bag of potatoes. She never went back to that store. I live in a wooded area. We have wood roaches that fly.
You cannot starve roaches no matter how clean your house--you have to kill them. They don't need your food. They will live quite well on wallpaper paste, soap, and the rotting wood from a leak.
If you get rid of those things, they may take to your beds to eat the dead skin from your sheets or worse, right off your body.
It is true that the less "food" there is, the less likely it is that they will make you home their own, but once there, you really can't starve them out in a normal home setting.
I rented a house that was roach-free until the summer months came and things got hot. Although they "went away" shortly after things started to cool down, I decided to move.
Prior to setting up shop in the new home, I had an exterminator come and spray around the garage and interior of the home as a preventive method. He said that it's impossible to completely rid ourselves of ALL pests, but one preventive measure he recommended was to put a cup of bleach down each sink drain and bathtub drain on a monthly basis. The bleach will dissolve the build-up that roaches use to climb up the pipes.
Caulk all the crevices and all the baseboards in your home, cockroaches are flat and can get into everything. Put down fly sticky traps where you can't reach under the sinks etc. It will help a lot!