I used to freeze my work (steel toed) shoes and my gym trainers over night, every night, in my freezer. Kills the stinky grown stuff. That, in combination with odor eaters, several sock changes in a day, and loosening em up and opening them up a bit in some sunshine for a few hours to dry out... Powders help. I go for the nuclear option; of all of the above, all at once, every day and frozen solid all night. The freezer thing really works. Double bag em, get em frozen solid while you sleep.
Funny, now that I think about it, I haven't had feetsy odor issues in years. A bit of athletes foot last year, but that was easy enough to remedy.