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Photographs of mold culture test kit results: this article illustrates common results of mold test kits that use a culture medium, and along with several companion articles listed here, it explains the availability and usefulness of eye-level or low-power magnification photographs of mold growing on mold culture plates, settlement plates, and mold test kits to try to identify indoor mold contamination.
Mold Photos in Petri Dishes - Not so Useful for Environmental Sampling and Mold Identification - What Level of Magnification is Needed to Identify Mold?
Following the list of some of our online guides to building mold just below, we include photographs of what mold looks like when growing on culture media commonly used in home test kits for mold.
In this article series we discuss the validity of nearly all of the popular mold testing methods currently in use, pointing out the strengths and weakness of each approach to mold sampling in the indoor environment, beginning with air sampling for airborne mold levels indoors.
Mold Test Kit Culture Plates: Why Can't I Find More Photos of Mold in Petri Dishes?
I was disappointed as there were no photos at all of petri dish examples of mold, and this is the way most of us out here will be testing for mold. So, how do I explore what mold I have in my petri dish test? I have quarter sized discs of black/dark green mold growing. I did the airborne mold test.
My dog is always coughing and I am in pretty good health but feel a slight "tug" in my breathing, a slight heaviness in my lungs but not bad. I rent my apartment and my landlord is a total tool.
What can I do financially and health wise to explore my situation? Thanks for any tips!!!
- Tony K
Reply: Microscopic Examination of Mold is Necessary for Reliable Identification
By Eye Examination of Culture Plates or Petri Dishes to Identify Mold?
The short answer is that you cannot reliably identify what mold is found in a petri dish simply by looking at some photos or color charts. Some mold genera or species might be ruled "out" or "possible" but expert examination of the sample using high-powered microscopy (or another definitive method) is needed.
We do have some photos of mold in petri dishes posted just above and online, at other of our online articles about the role and limitations of using mold cultures as "home test kits" at Cultures to "Test for Mold". (You'll see there that what grows in culture is not necessarily the dominant or most significant mold that is present in a building.)
Traditionally, petri dish or culture plate photos were included in early mold taxonomy texts, where color and texture of mold growth at that scale assisted in identification of cultures of a known genera down to species level.
These were photos of mold cultured in laboratories where it is sometimes possible to separate a genera of mold (Aspergillus sp.) into species or groups of species (Aspergillus niger) based on color and other macro-characteristics.
In the closeup of a mold culture petri dish growth shown in our photo at above-right, high-powered microscopic examination was necessary to identify Penicillium sp (photo at left) as one of the several mold genera growing among these green, gray,and dark gray colored mold colonies.
Sometimes we can make a pretty good guess about mold identification by the naked eye, if we see a particular color and texture of mold on a particular surface. For example this photo of mold on an orange is showing what is most likely a species of Penicillium.
But in general that "by eye" mold identification approach is not reliable.
Stereoscopic Microscope Photos of Mold to Identify It?
An "in-between" level of magnification, between using the naked eye to look at mold culture growing in a petri dish and using a high powered microscope is the use of a stereo microscope to magnify mold growth on surfaces such as on culture media in a petri dish.
For example, our stereoscopic microscopy photo of Fuligo septica (left) is characteristic of that particular fungus.
Stereoscopic mold photos are often beautiful (like this stereoscopic photo of Stemonitis mold growth structures taken in our lab) and may be helpful in identifying a mold genera. Here, for contrast, is a high power microscope photo of Stemonitis mold spores.
But stereoscopic magnification is inadequate for reliable mold identification.
High Powered Microscopic Identification of Mold Spores
For environmental samples in which we need to identify mold genera/species or other particles, it's a different story.
As we operate a forensic lab that processes lots of materials including mold, collected by various means, we see that while petri dish photos are pretty, they are not diagnostic, nor can they be used alone for mold identification at that scale.
We need to examine mold structures and spores at 300x to 1200x to actually identify genera/species reliably. See MOLD by MICROSCOPE for examples.
The Fuligo septica mold spores in our photo provide very different information than what we can get by eye looking at a mold culture plate or petri dish.
At MOLD "TESTING" vs. MOLD "PROBLEM IDENTIFICATION" we discuss the question of what sorts of mold testing are most useful and which are actually diagnostic, giving information about the presence of a mold problem with enough information that you know what to do about it.
Additional Comments on Mold Culture Identification
Mold cultures involve the collection of particles by air sampling pump, by
gravity settlement, or by lift from a surface using a swab or tape. Some
sampling equipment (Anderson™ spore traps) can collect spores directly into a
petri dish of culture medium, and are used for "viable spore sampling in air."
Mold Culturing is useful for genera speciation once you have
collected a single or dominant sample whose importance (frequency in the
building) you already know. As a "home test kit" for the presence of
problematic mold in a building this is an unreliable method, as we describe
below at "shortcomings."
Our lab photo (above left) shows two different mold colonies growing on a culture plate where individual spores settled out of the air onto this surface.
Frequently Asked Questions (FAQs) about photographs of mold growth on culture plates
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MOLD APPEARANCE - WHAT MOLD LOOKS LIKE - What Does Black or Dark Indoor Mold Look Like? Black Mold spores in the Home - a Photo ID Library. What toxic black mold or other indoor mold looks like in buildings.
MOLD GROWTH on SURFACES, PHOTOS - What Does Mold Look Like on Various Materials & Surfaces? An extensive photographic guide to mold as it is found growing on various building materials & surfaces. Also see MOLD GROWTH on SURFACES, TABLE OF - a Table of Kinds of Mold Growth Found on Building Surfaces, lists mold genera/species most often found on specific building surfaces, materials, or contents
MOLD by MICROSCOPE - Mold spores under the Microscope - a Photo ID Library for detection and identification of toxic or other mold
MOLD RELATED ILLNESS SYMPTOMS - Mold Related Illness: Index of Symptoms. Readers should not rely on this document for medical diagnosis and instead should consult with their physician or with a specialist such as a medical toxicologist
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
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Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home",
U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention in Home Vegetable Gardens,"
Department of Plant Microbiology and Pathology,
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.