Where Does Penicillium Mold Grow? Everything You Need To Know

Helen Skeates
Helen Skeates
22 min read

Learn where penicillium mold grows by reading this article. Indoors and out, it can be cultivated, but the specifics will be discussed later.

Check out the entire article if you’re interested in penicillium mold growth!

What Is Penicillium Mold?

There are about 300 species of Penicillium, some of which are common and some of which are not. It is possible to find Penicillium mold in a wide spectrum of hues.

They are most generally known as blue or green molds since their colonies can be white, blue-green, pink, or yellow. They develop and spread swiftly, just like other kinds of mold.

Color is typically used to distinguish mold from one another. In this post, you’ll learn how to identify mold by looking at its color.

Penicillium mold differs from penicillin, which is something you should know. The latter is better for your health, while the former has negative consequences.

Where can you find penicillium mold?

Because Penicillium mold spores are airborne, they can be found almost anywhere. They can be found on a wide range of surfaces, from the earth outside to the possessions in your home (e.g. leather, clothing, etc).

Mold Identification 101: Where Does Penicillium Mold Grow? - Krostrade

Penicillium thrives on decaying plants, soil, grains, compost, and rotting fruit in an outdoor environment, where it thrives. While indoors, they can also be found on things like carpets, wall paper, dust, and even freshly painted walls and ceilings.

When Penicillium mold’s development requirements are met, it thrives. Moisture, food source, and oxygen are the three requirements for penicillium mold growth.

Oxygen is quite literally everywhere, so this condition is not difficult to meet. Mold contamination occurs only when all other conditions, such as a food source and adequate moisture, have been met.

Are they dangerous?

Penicillium mold, like all molds, has negative health impacts. Toxic substances are exuded by a species of penicillium that creates mycotoxins.

As well as on food, Penicillium flourishes. They can induce gastrointestinal distress if consumed.

If you’d want to learn more about the dangers of consuming mold, check out this article. Mold can induce allergic reactions in addition to stomach problems.

Respiratory or integumentary allergies are possible. Mold exposure might induce or worsen asthma attacks in members of your household.

You should be extra cautious of mold now that you are aware of the dangers it poses to your health. To be on the safe side, you can compare the air samples from inside and outside.

No matter how many or how few spores differ, you are secure. If your interior air sample contains more spores than your outdoor air sample, you should take action right away.

If you’d want to get your air quality checked for penicillium mold spores, you can do it with the help of a professional.

Despite its negative impact on human health, some species of penicillium are actually useful to us. Cheeses including Brie, Camembert, and Roquefort contain penicillium.

Unless it’s over its expiration date, these cheeses are safe to eat. Humans can benefit from penicillin as well.

But keep in mind that not all mold development in a home is harmful, and it’s important to know that. A number of procedures are required before they can be utilized in food or medicine without causing harm.

Who discovered Penicillium?

Dr. Alexander Fleming, a physician and bacteriologist at St. Mary’s Hospital in London, England, developed penicillin in 1928. Staphylococcus bacterium strains were being cultured at the time, and he noticed that some of the colonies he’d left on the workbench had unusual green contaminations. Doctor Fleming discovered that the Penicillium notatum mold had slowed the formation of Staphylococcus bacteria colonies. This organism was identified as P. rubens in the present day (5, 6).

After a miscarriage and an illness that led to blood poisoning and nearly took her life, Anne Miller was the first patient to be successfully treated with penicillin in March 1942, 14 years after the discovery of penicillin. (6)

Blood poisoning was common at the time because there were no specific antibiotics for bacterial infections. Dr. Fleming was the first to discover that Penicillium mold can secrete an antibiotic material and the first to synthesize a concentrate of the active ingredient, penicillin, in 1928.

Scarlet fever, pneumonia, meningitis, diphtheria, and gonorrhea, a significant sexually transmitted disease at the time, may all be treated with the microbial inhibitory factor, as Dr. Fleming discovered. During the following twelve years, he undertook a great deal of experimentation and distributed the original mold. For more than a half-century, penicillin has been considered as one of the biggest advancements in therapeutic medicine (6, 7).

Common species of Penicillium

A paintbrush-like appearance of their conidiophores (asexual structures that contain spores) led to the name “Penicillium” being given to this bacterium. Penicillium, a genus of bacteria, now has over 300 recognized species.

P. chrysogenum (syn. P. notatum), P. purpurogenum, P. janthinellum, P. digitatum, and P. marneffei (syn. Talaromyces marneffei) are some of the most common Penicillium species. In certain cases, microscopic characteristics and colony morphology can be used to identify these species, while in others, molecular identification is more trustworthy (8, 9).

What to do when there is mold growth in your home?

The first step is to figure out what kind of mold is growing in your home. Also, investigate the source of mold infection.

The problem is likely water damage, so find out what caused it and fix it. It’s also possible to hire an expert to handle this issue.

Step #2: Start removing mold from the surface if the infected area is small. Wear safety gear when doing so.

Cleaning mold necessitates the use of a respirator, safety goggles, and rubber gloves. To avoid getting sick from mold exposure, you can wear a full-body suit or an old long-sleeved shirt.

Apply a mold-killing substance, either commercial or natural, to the mold-infested surface in order to remove the mold. Until all mold spots are gone, keep reapplying the solution.

We recommend hiring a professional if the mold is found in an area of your home that is difficult to access.

Penicillium mold prevention tips

Deny mold food sources and moisture to inhibit mold growth. As a result, regular cleaning of your home’s crevices is a need.

Ventilate your home thoroughly as well. To prevent mold spores from settling in your home, make sure there is enough ventilation.

Consider purchasing an air purifier or a dehumidifier if opening windows isn’t an option owing to the time of year. If you’re concerned about indoor air quality, having both is an option.

If mold returns despite multiple cleaning and removal procedures, it is possible that other places have been affected with mold. Mold continues to grow as a result of this.

Hire an expert mold inspector if you’re in that circumstance.

Penicillium: Understanding The Risks

Penicillium is most known for its role in food spoiling, as many species favor organic biodegradable material as their preferred habitat. Because of this, they play a significant role in the growth of visible mold on food goods that have been incorrectly stored, such as citrus fruits, for example. Apples are ruined by P. expansum. Foods contaminated with Penicillium should be avoided.

Toxic mycotoxins are produced by a wide range of organisms. Penicillium, unlike many other species of mold, can survive even in conditions when relative humidity is low, making it a particular source of concern when preserving foods like seeds and grains.

Penicillium can, however, also be an airborne threat;

Residents and public buildings were discovered to be home to a variety of organisms. Fungi can be easily carried from the outdoors and thrive indoors using building debris or collected dirt to gather nutrients for growth,” Wikipedia reports. The minimal moisture requirements of spores allow them to quickly establish themselves indoors. A low relative humidity does not mean that Penicillium cannot grow indoors. As long as there is enough moisture on a given surface, Penicillium can thrive.

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In locations with a lot of rain, this is more likely to happen. Penicillium spores are so ubiquitous in the indoor air of residential dwellings in coastal areas of the United States and the United Kingdom that spore levels indoors actually exceeded outdoor levels by 16 percent. Even ceiling tiles can promote the growth of Penicillium, according to the paper Growth evaluation of fungus (Penicillium and Aspergillus spp.) on ceiling tiles by John C.S. Chang For this to be true, there needs to be an interior humidity level of at least 85% and tile moisture content of at least 2.2%.

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The hazardous mycotoxin “ochratoxin A,” produced by this mold in indoor environments all over the world, is nephrotoxic (damaging to the kidneys) and very likely carcinogenic as well (cancer causing). Although Penicillium infection is more common in cold climes, this type of mold creates poisons when it grows on stored cereal grains.

Penicillium produces a number of other mycotoxins, including:


Researchers believe that Patulin is a carcinogen, however they are unable to link chronic exposure with specific cancers. In rat trials, it was found to be harmful to mammals as well. Patulin is highly hazardous to mice and rats at relatively high dosages.” The stomach and small intestine become inflamed, distended, and hemorrhage as a result. They found that oral administration of patulin to mice and rats resulted in LD50 values (the lethal dose) of 20-100 mg/kg body weight. (Patulin, Richard Lawley, 30 January 2013)


Toxic to livestock’s kidneys, Citrinin behaves like a milder form of ochratoxin A. It is commonly inhaled by livestock (through Penicillium spores) as a result of the animals’ regular exposure to contaminated grain. Citrinin-exposed poultry had kidney damage, according to a report by Trilogy Labs: “Poultry [were detected] with the effects largely on the kidney of these species.”. Citrinin appears to be less hazardous to chickens than oosporein or ochratoxin A, two other significant nephrotoxic mycotoxins, in terms of its relative toxicity.

Concerns were also raised in the paper about citrinin’s potential impact on other vital organs: “High citrinin levels may harm the liver as well as the kidney. Citrinin poisoning in chicken is commonly characterized by an increase in water intake and diarrhea. Low levels of dietary citrinin have been shown to elicit these symptoms.”


When exposed to high dosages of citreoviridin, lab animals show paralysis of the limbs, which is followed by convulsions and respiratory arrest. “Citreoviridin is produced by Penicillium citreonigrum, toxicarium, citreoviride,charlesii and ochrosalmoneum and Aspergillus terreus,” according to the Toxic Black Mold website. Mice, cats, and dogs have been shown to suffer “paralysis of limbs; vomiting; convulsions; cardiovascular damage; and respiratory arrest.”

Mycotoxin-tainted rice and maize are common sources of citreoviridin, which has been linked to a “Beriberi-like sickness” in Japan and China where rice has been infected with the toxin. Keshan disease has also been linked to chronic exposure to tainted cereals in China.”


For the most part, penitrem mycotoxins are released into the indoor air by Penicillium species such as crustosum, cyclopium, and commune, but they can also enter through foods that have already been contaminated (such as meats and dairy products). It is also neurotoxic, as evidenced by the fact that it has poisoned dogs and humans both. Inhaling Penitrum is likely to have a negative impact on the body as well as the digestive system.


As a neurotoxic, verrucosidin is well-known in the United States, where it has long been linked to a neurological condition in cattle. (1991) (Journal of the American Veterinarian Medical Assoc 179:480-81).

There are a number of other mycotoxic acids produced by Penicillium, including penicillic acid and cyclopiazonic acid, both of which are acutely toxic to mammals and have been implicated as the “casual causes of liver and kidney lesions in mice fed with infected corn”

Penicillium is also known to create tropolones puberulic acid and puberulonic acid, a mycotoxin with an unknown structure, and a -(L)-malic acid, which is a proteinase inhibitor, according to mold authority Mold Help.org. Exposure to penicillium alters human DNA, as it does with all toxigenic fungi. This substance has the potential to cause long-term and severe harm to the nervous system, immune system, and psychological well-being.

Infections caused by Penicillium marneffei can be both localized and diffuse.” Affected organs include the bone marrow as well as the skin and soft tissue. Symptoms of these diseases, which can come from either ingestion or inhalation, are common. Examples of these symptoms include: fever, anemia, skin lesions and lesions, cough, hepatomegaly and adenopathies, as well as lung infiltrates and adenopathies.

Immunocompromised individuals should be aware of several Penicillium species that do not generally release harmful toxins. Patients with AIDS are more susceptible to deadly opportunistic infections when P. Marneffei is present, making its isolation from blood an HIV marker in locations where it is. Third most prevalent opportunistic pathogen among HIV-positive patients in Southeast Asia is this kind of Penicillium. Infected bamboo rats frequently spread the disease to humans.

Identifying Penicilium In Indoor Environments

Penicillium, a fungus that thrives in food storage, can be easily identified. This is due to the mold’s characteristically brilliant blue-green or yellow hues… It’s far more difficult, however, to correctly identify the numerous forms of fungal mold that might permeate indoor air. Many species of Penicillium can only be correctly identified by taking a sample by a certified indoor air expert.

If you have access to a microscope, you can determine if you are dealing with a Penicillium mold kind. phialides, which are thick broom-like spore-bearing structures, are the best way to identify them. Flask-shaped phialides with spore chains (conidia) extending from their tips are the most common form. Typically, the spores are green in hue. Even if they don’t have a consistent shape, they’re usually circular and have smooth to roughened walls. (Click on this link for more information on how to recognize Penicillium under a microscope.)

A Penicillium species identification technique, however, can only inform you that you’re dealing with a species of Penicillium, not the exact species or the type of mycotoxins it’s creating. Samples must be taken and sent to a lab for this kind of information.

Penicillium (most commonly P. Chrysogenum, which seems particularly well-adapted to infiltrating the air of residences and buildings), can usually be located either:

  • Thriving in cellulose-based environments like as those found in buildings and dwellings (e.g. plants, wood, paper, etc.). Where there is enough moisture, Penicillium can be found on old mattresses and upholstered furniture, carpet, wallpaper, and even the insulation in fiberglass air vents. Building materials, books, cartons, and timber that have been exposed to moisture are particularly hazardous when stored in wet basements.
  • Abandoned or damaged structures are particularly vulnerable to Penicillium infestation because water can seep in through cracks in the wall or ceiling, or through decaying wood or chipboards. It is very recommended that a professional mold inspection be performed before any repairs are made to your home’s roof or foundation.
  • Penicillium thrives in decaying organic materials, such as plant detritus and food that has been rotting for a while. That is why it is important to get rid of any compost piles, houseplants that have been neglected, or even damaged food from the indoors as quickly as possible.

Are Penicillium molds dangerous?

Penicillium molds, which are common food spoiling agents, pose a threat to human health. So as a result of the presence of harmful chemicals known as mycotoxins in certain Penicillium species (10). Over 30 hazardous chemicals have been found in Penicillium infected foods, both for human and animal consumption (11). It’s better to be cautious than sorry and throw out any food that appears to have mold on it.

Penicillium spores can also cause allergic reactions in people who are susceptible to mold when inhaled. As a result, large concentrations of Penicillium spores in indoor environments can lead to a wide range of health problems, from moderate irritation to asthmatic attacks.

What are safe levels of Penicillium?

The Environmental Relative Moldiness Index (ERMI) was created by the Environmental Protection Agency and the Department of Housing and Urban Development of the United States to measure indoor air quality. Air quality and mold contamination in U.S. homes may now be measured with this simple, repeatable test.

DNA-based technology is used by ERMI to determine whether water damage-associated hazardous mold species are present in examined homes. It also measures the amount of mold material in use (spores and hyphal fragments). Additionally, ERMI looks for mold species that aren’t often associated with water damage, but are known to have negative health impacts anyway. It can also be used to estimate the number of items in a collection.

Seven of the 36 mold species on this list are Penicillium species. Among these are Penicillium brevicompactum, Penicillium corylophilum, Penicillium crustosum, Penicillium purpurogenum, Penicillium spinulosum, and Penicillium variabile Respiratory irritations and allergies, as well as more serious illnesses including opportunistic lung mycosis, pneumonia, and asthma, are all linked to these penicilli (12).

What are the allergy symptoms associated with Penicillium mold?

Aside from Penicillium, the majority of molds produce a large number of spores. These spores are dispersed into the air, where they can be inhaled or land on various surfaces around the house. To make matters worse, spores are water-resistant and may endure long periods of time without water (13). Everyone’s reaction to Penicillium mold spore inhalation is distinct. Asthma and allergy responses can affect different people in different ways. Cross-reactivity between non-allergenic fungi and Penicillium species can also lead to anaphylactic reactions due to structural similarities (14).

For the most part, our immune systems can identify and eliminate thousands of fungal spores that we breath each day. Individuals with allergies may become hypersensitive to the presence of these spores. Sneezing, nasal congestion, itching lips, mouth, and nose are just a few of the symptoms you may experience if you are allergic to Penicillium. Anaphylactic shock can occur as a result of hyperallergy.

What are the health effects of Penicillium mold?

Mycotoxins produced by Penicillium fungi can cause a variety of health problems. Ochratoxin A, Rubrosulphin, Viopurpurin, Viomellein, Citreoviridin, Citrinin, Islanditoxin, Patulin, Penitrem, Viomellein, Rubratoxin, and a slew of others are examples of this class of toxin. Toxin production can range from very small amounts to large quantities. Exposure to these poisons over time (either by inhalation or ingestion) could have detrimental effects on one’s health because of the potentially significant biological reactions they can cause. Toxic to internal organs, they can cause cancer, birth defects, immunosuppressant effects, and have a negative impact on kidney function (15).

How to remove Penicillium mold?

As a matter of course, any mold that has been found in your home should be removed as quickly as possible. Many molds are harmful to human health, especially to infants, those with respiratory conditions such as asthma, elderly people as well as those with poorly functioning immune systems.

As a matter of course, any mold that has been found in your home should be removed as quickly as possible. Many molds are harmful to human health, especially to infants, those with respiratory conditions such as asthma, elderly people as well as those with poorly functioning immune systems.

Definitely, any mold that has been found in your home should be eradicated as soon as possible—the sooner, the better. Many molds are dangerous to human health, especially to infants, those with respiratory diseases such as asthma, elderly persons as well as those with weakly functioning immune systems.

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The sooner you eliminate any mold from your home, the better off you will be. There are several molds that are dangerous to human health, particularly to newborns, those with respiratory disorders like asthma and the elderly, as well as those with weak immune systems.

  • N-99 or N-95 face mask
  • Full body suits
  • Protective eyewear
  • Shoe covers that can be thrown away after use
  • Gloves that can be thrown away.

How to prevent Penicillium mold from growing back?

To ensure that Penicillium molds do not return to your home, you must take steps to prevent them from re-emerging. In order to keep mold spores from spreading throughout your home, make sure it is adequately ventilated and has lots of air flow. As a result, the potential for mold contamination will be reduced to a bare minimum. Air purifiers and dehumidifiers can also assist lower the relative humidity in your house.

If you have a mold problem that isn’t going away, you should hire a professional mold removal company. Mold Busters’ mold examinations and visual assessments typically uncover hidden moisture problems that contribute to continuous mold contamination and decreasing indoor air quality in houses.

To schedule a mold inspection, please call us now.


When you know where penicillium mold grows, you can prevent it from spreading by following our advice. In addition, we hope that our health warnings were enough for you to be cautious about using it.

Helen Skeates

Helen Skeates

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