I tried a lot of things, but “Orange Guard” seemed to work best. It’s not poisonous to humans, it has a strong orange peel scent but it’s not too objectionable. I kept spraying it wherever I saw ants inside or outside, in fact I think what finally solved my problem was finding the outside trails they had going up the side of my house and dousing them daily with Orange Guard.
And of course you have to keep all food and drink inside sealed and crumbs and drips off of everything.