I had the same problem. Clean your entire kitchen, all counters, floors, and anywhere some crumbs may be. Go to the store and get liquid ant killer. you will place it on small areas. The ants will come strong to the liquid. Ants take their food back to the living place. Which with the liquid, it wont kill them instantly! They will take it back to their nesting place and as they eat it...it will kill them. Also, as ants walk across your counters - they leave a trail for other ants so they know where the food is.