The "foot odor" is the unpleasant odor of perspiration from the feet, whose official name is bromhidrosis. This word has a Greek origin, from the junction of bromus, which means "bad smell", and hydros, which is “water”.
Perspiration itself does not have an unpleasant odor, as sweat is basically composed of water (99%), sodium chloride, low molar mass carboxylic acids, urea, salts of iron, potassium, ammonium, lactic acid, proteins and others components. The problem is that on our skin, especially on our feet, there are thousands of bacteria, which are single-celled micro-organisms of microscopic size (0.2 to 1.5 μm in length).
Bacteria feed on pieces of skin on our feet, on accumulated sweat and also on oils made up of fatty acids. After feeding on these fatty acids, they produce some carboxylic acids that are really responsible for the unwanted "foot odor" smell.
The cause of foot odor is the bacteria present on the skin
One of the main carboxylic acids produced is valeric acid (C4H9—COOH)
— name that comes from latin valere (“Valerian plant”) — which is also responsible for the smell of the cheese roquefort.Other compounds produced by these bacteria that have an unpleasant odor are butyric acid (C3H7COOH), methanethiol (H3C-SH), ammonia (NH3) and butanedione.
If the person has poor foot hygiene, the problem is aggravated because the amount of bacteria increases, as they like a hot and humid environment, and the amount of oils too rises.
So, to get rid of the smell of foot odor or at least avoid it, you should first wash them with soap and water and dry them well, even between your fingers. The use of antibacterial and fungicide soaps is also valid, as it prevents the proliferation of bacteria on the skin.
In addition, to treat foot odor, it is important to use antiseptic talcs that also act on the degradation and inhibition of fungi and bacteria. These products have as constituents, for example, zinc stearate, which kills fungi, and boric and benzoic acid, which deteriorate bacteria.
Also remember to vary your shoes a lot and wear socks that allow better ventilation for your feet.
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/composicao-quimica-chule-como-trata-lo.htm