It's quite normal to wear the same pair of jeans, a sweater or even a t-shirt more than once. But what about your socks?
If you knew what was really in your socks even after a day of wearing them, you might think twice before doing so.
Our feet are home to a microscopic rainforest of bacteria and fungi, typically containing up to 1,000 different species of bacteria and fungi. The foot also has a more diverse range of fungi living on it than any other region of the human body.
The skin of the foot also contains one of the largest amounts of sweat glands in the human body.
Most foot bacteria and fungi prefer to live in the warm, moist areas between the toes, where they feed on nutrients from sweat and dead skin cells. The waste products produced by these microbes are the reason why feet, socks, and shoes can become smelly.
For example, the bacteria Staphylococcal hominis produces an alcohol from the sweat it consumes that produces a rotten onion odor. Staphylococcus epidermis, on the other hand, produces a compound that has a cheesy smell. Corynebacterium, another member of the foot microbiome, creates an acid that is described as having a goat-like smell.
The more our feet sweat, the more nutrients will be available for foot bacteria to eat and the stronger the odor will be. Because socks can trap sweat, it creates an even more optimal environment for odor-producing bacteria. And these bacteria can survive on fabric for months. For example, bacteria can survive on cotton for up to 90 days. So if you go back to wearing unwashed socks, you will only allow more bacteria to grow and thrive.
The types of microbes that reside on socks not only include those that normally inhabit the foot microbiome. They also include microbes that come from the surrounding environment, such as home or gym floors or even outdoor soil.
About the author
Primrose Freestone is a senior lecturer in clinical microbiology at the University of Leicester.
This article was first published by The Conversation and is republished under a Creative Commons license. Read the original article.
In a study that looked at the microbial content of clothing that had only been worn once, socks had the highest microbial count compared to other types of clothing. The socks had between 8 and 9 million bacteria per sample, while the t-shirts only had about 83,000 bacteria per sample.
The species profile of socks shows that they harbor harmless skin bacteria, as well as potential pathogens such as Aspergillus, Candida and Cryptococcus, which can cause respiratory and intestinal infections.
The germs that live on your socks can also be transferred to any surface they come into contact with, including your shoes, bed, couch, or floor. This means that dirty socks could spread the fungus that causes athlete's foot, a contagious infection that affects the skin on and around your toes.
That's why it's especially important for people with athlete's foot not to share socks or shoes with others and to avoid walking around with only socks or bare feet in gym locker rooms or bathrooms.
What lives in your socks also colonizes your shoes. This is why you may not want to wear the same pair of shoes for too many days in a row, to give the sweat time to dry completely between wears and prevent further bacterial growth and odor.
Foot hygiene
To reduce foot odor and reduce the amount of bacteria that grows on your feet and socks, it is a good idea to avoid wearing socks or shoes that make your feet sweat.
Washing your feet twice a day can help reduce foot odor by inhibiting bacterial growth. Foot antiperspirants can also help, as they stop sweat, thus inhibiting bacterial growth.
It is also possible to buy socks that are directly antimicrobial to foot bacteria. Antimicrobial socks, which contain heavy metals like silver or zinc, can kill bacteria that cause foot odor. Bamboo socks allow for greater airflow, meaning sweat evaporates more easily, making the environment less hospitable to odor-producing bacteria.
Therefore, antimicrobial socks could be exempt from the single-use rule depending on their ability to kill bacteria and fungi and prevent sweat buildup.
But for those who wear socks made of cotton, wool or synthetic fibers, it is best to wear them only once to prevent foot odor and avoid foot infections.
It's also important to make sure you wash your socks properly between uses. If your feet don't smell unusual, it's okay to wash them in warm water at 30 to 40°C with a mild detergent.
However, not all bacteria and fungi will disappear with this method. Therefore, to thoroughly disinfect the socks, use a detergent containing enzymes and wash them at a temperature of 60°C. The enzymes help loosen the microbes from the socks while the high temperature kills them.
If washing at a low temperature is unavoidable, ironing the socks with a hot steam iron (which can reach temperatures of up to 180-220°C) is more than enough to kill residual bacteria and inactivate the spores of any fungus, including the one that causes athlete's foot.
Air drying your socks is also a good idea, as the ultraviolet radiation from sunlight is antimicrobial to most bacteria and fungi on socks.
While socks may be a frequently reused item of clothing, as a microbiologist I would say that it is best to change your socks daily to keep your feet fresh and clean.
