Hi S. -
We bought a ton of the ultrasonic pest repellers made by Black & Decker. You can get them at Target or hardware stores. They come in a 3-pack for $20, and I think we've bought 3 packages...we have a lot of rooms, and since the ultrasonic waves don't go through walls, you need them in every room. We have 2 in our basement and 2 in the living room. They are simple little plug-in things that emit waves that we can't hear, but that disrupt the nervous systems of bugs/small rodents so that they leave your house (supposedly).
We had a few plugged in and saw 2 mice come up through the heating vent one night in our living room, so we bought a bunch more and also have some traps set in the basement. So far we've only had to take care of 2 mice in the traps. I love these because they are humane and they keep away bugs as well. We stopped seeing earwigs and I have no spiders now - at least visibly, LOL.
I can't say they would work for you (we started using them just as the mice began sneaking in) but I think they're worth a try! The package says the waves will not travel into walls, etc. But I would at least plug a couple into your kitchen and see if that gets them away from your food, and if they can't get to the food perhaps they'll move on.
You can't use these if you have small pets like hamsters, though.
Good luck!