I need help getting a sour milk smell out of my car?

I had about 2 teaspoons of milk in a half gallon jug in my car. It was only in there for 3 days, and it was shoved underneath the seat which is why I forgot about it. Anyways, due to the heat, it exploded and sent curdled milk all over the back seat. My husband washed and vacuumed the car, and it still has a sickening stench. Does anyone know what I can do to get rid of the smell?