Do your dog’s feet by any chance smell like corn chips? I am guessing that you are experiencing the infamous syndrome that Dogster folks refer to as Frito feet (click the link to see what I have written on the subject before).
Dogs’ feet have areas of reduced air circulation. The spaces between the toes on the top of the feet and between the pads on the bottom of the feet are most prone to this. The reduced air circulation in these areas allows more moisture to build up in these spots than elsewhere on the body.
Bacteria and yeast grow in slightly greater numbers in these humid areas. The bacteria and especially the yeast give off a slight odor that causes the characteristic smell of Frito feet.
The overwhelming majority of dogs with Frito feet do not have pathological infections. The syndrome is harmless. Eliminating the odor is very difficult, but it also isn’t necessary.
If your dog’s foot odor is truly offensive you should have a vet check him out to confirm that the skin is healthy and that something else isn’t going on. But I’m guessing that nothing’s wrong.