daisyl is right in the respect that harmless fungal organisms are common on the skin.
Mum & Geeg are also right, we are coated, literally in bacteria.
Both are not an issue under normal circumstances.
The odour that nail techs (pedicurists) generally face is from an overgrowth of bacteria
"brevibacteria" (which is naturally on us) and only occurs when there is a build up sweat that can not evaporate.
Athletes foot, or other fungal 'infections' occur when an aggressive and specific fungal spore (tinea - Trichophyton) is given the opportunity to grow, ie, cracked or broken skin. then and only then will it burrow in and grow within the skin. Good hygene & foot health are the best prevention.
In answer to the original post - your tutor is misleading, as the VAST majority of foot odour will be bacterial.
hope that helps everyone.