Bio-Safe Pest Control?

I have some little ants that are making their Springtime debut in my kitchen -- and they won't go away! I've tried keeping my doorway sealed, and sprayed vinegar on the doorway (as well as baking soda) to discourage them, but there's still an odd few that seem to make it through my 'barricades'. Any ideas? It's not an infestation, but annoying nonetheless.

I'd rather not go the chemical/toxic route, of course.