How harmful is black mold?


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What is black mold?


Since you want to understand what black mold is, you must first get to know mold.

Mold is a kind of fungus, which is characterized by more developed mycelium without large fruit bodies. Like other fungi, they have cell walls, living in parasitic or saprophytic manner. Some molds convert food into toxic substances, and some may produce toxins in food, that is, mycotoxins. Since the discovery of aflatoxin, the contamination of food by mycotoxin has attracted increasing attention. It causes great harm to human health, mainly manifested as chronic poisoning, carcinogenic, teratogenic, and mutagenic effects.

Black mold is not a type of mold as most people think. Black mold can include many kinds of molds. It is called "black mold" as it has dark green or black color. Stachybotrys chartarum is also a kind of black mold.

Black mold, like other molds, likes to grow in humid and warm places, such as your bathroom, toilet, kitchen, and basement. Black does not mean that it is more dangerous than other molds. There is currently no evidence that the color of molds is related to their toxicity.

How harmful is black mold?

1. Food poisoning

After eating moldy food, it may directly cause poisoning, or produce carcinogens, and poison the human body.

2. Mold infection

Molds reproduce directly in the human body, causing fungal pneumonia and other diseases, which are more common in some chronically ill people.

3. Allergic diseases

Allergic diseases can be caused by molds, such as bronchial asthma and dermatitis. In addition, mycotoxin has a strong tolerance to temperature, so it is better not to eat food contaminated by mold.

Places where black mold tends to appear and countermeasures

1. Clothes

There are generally three reasons for the growth of black mold on clothes. One is that the clothes are not washed clean, the other is that the clothes are not completely dried, and the third is that the clothes are placed in a humid environment. In the humid and warm summer environment, clothes are more prone to black mold.

So the question is, how to remove these irksome molds?

A. Aerobic washing powder

Soak the clothes in aerobic washing powder and wash them wet. Aerobic washing is a kind of washing powder that can inactivate mold and remove the moldy odor, which can greatly reduce the mildew stain on the fiber and the color. It should be noted that different bleaching agents should be used for different fiber types, and the color fastness test must be carried out.

If the dye cannot resist any oxygen bleaching, then use ammonia or detergent to test the color fastness, because this may improve the condition of the clothes. Humidity, lack of ventilation and sunlight will accelerate the growth of mold. Therefore, clothes placed in plastic bags should be treated immediately to prevent mold.

B. Washing rice water

Soak the moldy clothes in the rice washing water overnight to allow the remaining protein to adsorb the mold. The next day, the color of the rice-washing water became darker, and the mildew stains had been removed a lot. Wash it several times with soapy water.

C. Alcohol

Wipe with a 2% soap and alcohol solution, then wipe with 3%-5% sodium hypochlorite or hydrogen peroxide, and finally wash the clothes.

D. Mung bean sprouts

Put the tender green bean sprouts on the mildew spot, rub your hands vigorously, and finally rinse with water.

E. Radish peel

Wipe the moldy area with the radish peel and wash it.

2. Wall

Some of these wall black mold in the house will form black spots on the wall, and some are lush, which can even spread to the entire wall surface. The odor of the wall where mold grows is pungent. The composition of wall molds is relatively complex, and most of them are toxic. Long-term inhalation of these spores is very harmful to human health.

Mold prefers acidic and aerobic environment, and the most suitable growth temperature is between 25℃-35℃. They grow well under the condition of relative humidity 90%-100%, but if relative humidity drops to 80%-85%, mold growth becomes slow or even stagnant. As long as there are available nutrients such as carbon and nitrogen sources, and the temperature is appropriate, the relative humidity is high, and the oxygen supply is sufficient, molds will grow in large numbers, and the breeding molds will eventually cause varying degrees of harm to the wall.

A. Main indoor molds

a. Cladosprium
It is green and brown and has a strong vitality. Tile joints, caulking, PVC plastic wallpaper, painted surface, bonding surface, fiber wallpaper surface, etc. can find it easily. It can cause asthma, skin diseases and emit a strong odor.

b. Acremonium
Light brown mold, found in PVC plastic wallpaper, tile joints, mortar, rubber, etc.

c. Penicillium
It is generally called blue mold and it has blue, lavender, yellow-green and other colors, commonly found in PVC plastic wallpaper, adhesives, epoxy resin, urethane coating, etc.

d. Tricoderma
Green mold, commonly found in mortar, urethane, painted surface, epoxy resin.

e. Altenaria
Gray-black, green-black mold, commonly found in mortar, urethane, painted surface, PVC plastic wallpaper, etc., can deteriorate coating film and plastic.

f. Aspergillus
It includes black mold, engineering mold, etc.

g. Aureobasidium Pullualans
It is one kind of mold commonly found near breweries. Like black smoke adhesion, the moldy part becomes pitch black. It can be found in PVC plastic wallpaper, painted surface, tile joints, etc.

B. Hazards

Staying in an indoor environment contaminated by wall molds for a long time, people will show discomfort. The very symptoms are headache, chest distress, rhinitis, pharyngitis, fatigue, irritability, skin allergic reactions, etc. Microorganisms can release volatile organic compounds (Microbial Volatile Organic Compounds, mVOCs), which have pungent odor and irritate eyes. mVOCs can also cause nose bleeding, induce asthma and severe asthma.

Mold on the wall can make walls uneven, corrosion of the skin layer, shedding of the decorative layer, and blistering. At the same time, the building materials become soft and pulverized, and the performance of the insulation material is reduced. It can be seen that while the presence of mold affects the beauty and structure of the building, it also poses a serious threat to the service life of the building.

C. How to prevent wall mold?

a. Reduce indoor relative humidity;

b. Keep the surface temperature above the dew point temperature;

c. Use a water vapor protective layer to control the penetration of water vapor and air into the wall;

d. Prevent the wall from infiltrating due to rain and groundwater.

D. How to remove wall mold?

a. When molds have appeared on the wall, use a toothbrush to brush away the mildew stains, and then gently wipe with a soft cloth moistened with alcohol to dry the wall and prevent the growth of bacteria.

b. Pour bleach and water into a watering can in a ratio of 1:99 and spray it on the moldy wall.

c. Wipe the wall with a rag and then rinse with water. After the wall is dry, apply an anti-mold paint to keep it away from moisture for a long time. In addition, there is a convenient waterproof repair agent on the market, just spray it into the crack of the wall.

3. Shoes

In the rainy season, long-term rain, coupled with the high temperature in summer, increases the humidity in the air, and shoes that are not worn for a long time, especially leather shoes, are prone to mildew and spots.

a. If the leather shoes have mildew. You can mix alcohol and water in a ratio of 1:1, then use a soft cloth dipped in the mixture to wipe the leather shoes, and place it in a ventilated place to dry.

b. For white shoes, especially white canvas shoes, they will leave stains after they become moldy. So add a proper amount of white vinegar in the last rinsing. It is best to soak for half an hour, and cover the shoes with toilet paper when they are rinsed and aired so that they won't turn yellow.

c. For white canvas shoes, you can soak the shoes with water. Then put on the sulfur soap and stand still for a while, or put the shoes with sulfur soap in a sealed plastic bag. Expose it to the sun for 20 minutes, then scrub it off, because sulfur has the effect of bactericidal and bleaching!


Shoes must be cleaned before storage, and stored after drying! It’s best not to throw away the shoe box and the paper stuffed in the shoes. They will come in handy when you need to store your shoes.

You can buy a mold cleaner for shoes. Use a soft cloth or toothbrush with the cleaner and apply it to the moldy areas of the shoes. But the mildew cleaner can be irritating, so it is best to wear a mask and rubber gloves when using it!

If you want to store your shoes, then you must clean the shoes, especially the inside of the shoes, and the soles. Dry it fully in a ventilated place. Put shoe polish on the leather shoes, dry them, put paper in the shoes, put them in a shoe box, and finally put them in a shoe cabinet or somewhere dry and ventilated.

4. Chopping board

Most people use wooden cutting boards at home. Although wooden cutting boards are easy to use and load-bearing, they are prone to black and moldy after a long period of use, and they look filthy, so you dare not use them again. Therefore, some people like to take it out to expose to the sun, thinking that this will kill the mold, but instead, the sun cracks the cutting.

A. Baking soda and white vinegar

After the cutting board turns black and moldy, it will definitely not be cleaned with clean water. Therefore, you can pour a little white vinegar on the top, and when the white vinegar becomes slightly dry, sprinkle a handful of baking soda, let the baking soda completely cover the dirty area of ​​the cutting board, and let it sit for 15 minutes. After 15minutes, wipe it gently with a steel wire ball, and you will find that the cutting board is much cleaner. Because white vinegar has the effect of softening dirt, and baking soda has the effect of adsorption, using the two together will double the effect.

B. Ginger

In addition to being a seasoning, ginger can also be used to clean cutting boards. Some cutting boards have a peculiar smell, because meat, fish and seafood products are often processed on them. Such a cutting board makes people feel uncomfortable to use, and always feel that food will be contaminated. Therefore, ginger can be used to wipe the cutting board, so that you can remove the peculiar smell.

C. Salt

The price of salt is even lower. When you scrub the cutting board, you can sprinkle salt on it. This will not only disinfect it but also increase the friction and make the cutting board cleaner.


Whether it is black mold or mold of other colors, it is deleterious for human health. We should take multiple preventive measures, and if mold appears, we should deal with it on time.

Want to learn more about mycotoxins? Read What foods contain ochratoxin A?