Why do clothes that are dried in the shade smell so bad? The reason is...

Audit expert: Zhu Guangsi

Member of Beijing Science Writers Association

On rainy days, we can only make do with hanging clothes outside. But sometimes we find that the clean clothes with the fragrance of detergent emit a "strange" odor after drying in the dark!

This makes people feel very strange. Why do clothes that are dried in the shade smell so bad? Is it because the clothes are not washed clean? Is it because the laundry detergent used is of poor quality? Why can't the smell be washed away? Then how to deal with it? Let me explain it in detail below.

1Where does the smell of clothes drying in the shade come from?

On rainy days, the house feels damp both inside and outside. Such a high humidity provides a breeding ground for the ubiquitous bacteria and fungi to survive and reproduce.

If we provide some "delicacies" at this time, such as sebum and dandruff left on clothes by the human body, microorganisms can multiply in large numbers in this hotbed, thus producing odor.

Some people may wonder: There are sebum and dandruff residues on washed clothes. Is it because they were not washed clean?

Source: pexels

The answer is yes. Even if you use high-quality laundry detergent, soak the clothes carefully before washing, and wash them in the washing machine for a long time, it is still impossible to completely remove the residues on the clothes, including sebum, dandruff and microorganisms.

Studies have shown that various microorganisms adhere to the surfaces and gaps of textiles used by people in daily life, grow and secrete extracellular matrix in this environment, and form biofilms. Although we clean textiles regularly, it can only maintain a certain level of hygiene and cannot remove microorganisms that have formed biofilms.

Microscope image of Staphylococcus aureus, a common bacteria species on textiles (stained)

Source: Wikipedia

Normally, textiles that look smooth and flat are made up of numerous fibers when magnified. Fibers with rough textures and great twists are more likely to hold dirt, making it easier to wash them clean, resulting in the residue of microorganisms and sebum and dandruff.

The result of observation under a microscope is that the surface structure of natural fibers is rougher, so it is more difficult to clean. Common wool sweaters, silk satin, and cotton clothes are all difficult to clean.

In addition, natural fibers, such as cotton, absorb water more strongly than synthetic fibers, so at the same humidity, natural fibers provide a more comfortable moist breeding ground for bacteria.

But no matter whether it is a natural fiber or a man-made fiber textile, after washing, place it on a dry, sunny day and dry it thoroughly in a short time. Even if there are a small amount of microorganisms, sebum and dandruff remaining on it, it will not have much impact.

Source: pixabay
If you choose to dry in the shade, or in the warm and humid rainy season, there will be big problems. In a warm climate, surrounded by many sebum "delicacies", it is difficult not to let various bacteria and fungi "carnival". They multiply here in large numbers, eat, drink, defecate and urinate, and produce strange odors that make people frown.

But even in the rainy season, it is difficult to avoid clothes smelling bad. Why is this? This is where a bacterium called Moraxella osloensis comes in. Generally speaking, after washing clothes, the bacteria that originally produced odor substances are either washed away or lose the environment for large-scale reproduction as the clothes dry, and they cannot produce odor.

However, when clothes are dried in the shade, Moraxella osloensis will multiply in large numbers and produce a substance called 4-methyl-3-hexenoic acid, which smells similar to stinky feet and is the main source of the strange smell.

Source: pexels

Moraxella osloensis lives on the human body surface. People often take a bath and change clothes, and other bacteria on the body will compete with it for resources, so there is no obvious odor left on the body and clothes. But when drying clothes indoors or on rainy days, this bacterium can easily settle on freshly washed clothes. Because it is an aerobic bacteria, it also has a certain resistance to drying and ultraviolet rays.

So when you are outdoors during the rainy season, even if the clothes are finally dried in the shade and the humidity drops, most bacteria and molds will no longer grow, but Moraxella osloensis is still "tenaciously" alive and producing a large amount of odorous substances.

This is why clothes dried in the shade have an inexplicable odor that lasts for a long time.

2 Ways to Avoid Smelly Clothes

Drying clothes efficiently

In a dry environment, it is difficult for bacteria and fungi to multiply in large numbers, and a small amount of microorganisms will not have much impact on clothes. So when drying clothes, in order to reduce the residual moisture on the washed clothes, in addition to using a hair dryer to dry them, you can also take them out and shake them after dehydration to make the clothes flatter and reduce wrinkles; you can put clothes in a place with good air circulation to reduce contact between each other and clothes and walls, because air circulation is almost stagnant near walls, making it difficult to dry; you can put paper such as newspapers under the clothes to absorb water vapor as soon as possible.

In addition, choosing a clothes dryer or a washer-dryer can also effectively improve the odor problem of clothes.

Cleans clothes effectively

In summer, when you sweat too much, soak your clothes in clean water at 30°C-40°C for more than 30 minutes to allow the sweat to dissolve from the clothes into the water; normal clothes can be washed in rainy days with long-lasting antibacterial detergents or bactericides to maintain an antibacterial environment; if the washed clothes have odor, you can add a few drops of floral water to the clean water, soak for about 10 minutes before washing, or if conditions permit, add fabric softener or care agent and soak for a few minutes before washing. In addition, the washing machine must be disinfected and cleaned regularly. Although bacteria are very tenacious, as long as the sterilization is done well, the conditions for bacterial growth are eliminated, and the environment for bacteria to reproduce in large numbers is not provided, even clothes dried in the shade will not have obvious odor.