Saniservice Knowledge

Mold Library

A scientific reference to the most common indoor molds identified in Dubai homes—what they look like, where they grow, what they mean for health and buildings, and how to control them.

Hazard classes: Class A = toxic Class B = allergenic Class C = pathogenic. Occurrence, appearance, and microscopy keys align with our Dubai field chart.

Penicillium Class A

Where it thrives

Water-damaged materials, paints, fabrics, carpets, fiberglass insulation, mattresses; dust-rich zones.

Visual ID

Green to blue-/grey-green; sometimes white/yellow/pinkish; colonies velvety → powdery.

Visual Microscopy

Phialides producing basipetal chains of conidia in brush-like penicilli.

Mycotoxins

Species-dependent: patulin, ochratoxin A, citrinin (primarily food-borne concern).

Health Risks

Airways (nose/sinuses/lungs): allergen; rhinitis, wheeze, cough; can aggravate asthma in sensitized occupants.

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Aspergillus Class A Class B

Where it thrives

HVAC systems, water-damaged areas, dust-containing materials.

Visual ID

Long flask-shaped spores; many colony colors; often in long chains on surfaces.

Visual Microscopy

Conidial head & vesicle shape; hyphae/spore features guide ID.

Mycotoxins

Species-dependent: aflatoxins, ochratoxin A, sterigmatocystin, gliotoxin, etc.

Health Risks

Lungs & sinuses: ABPA (wheeze), chronic pulmonary aspergillosis (cough, weight loss), invasive aspergillosis in immunocompromised (fever, chest pain, hemoptysis).

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Trichoderma Class B

Where it thrives

Gypsum board, saturated wood, wallpaper, carpet/mattress dust, paint, AC filters.

Visual ID

White wool-like colonies with green patches.

Visual Microscopy

Hyaline phialides; colony texture is a strong field differentiator.

Mycotoxins

Peptaibols (e.g., alamethicin/harzianins); significance varies by strain and substrate.

Health Risks

Airways/skin: mainly allergenic/irritant; infections rare and usually in vulnerable hosts.

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Mucor Class B

Where it thrives

AC/ductwork with condensation; old damp carpets.

Visual ID

Thick patches, white/grey → beige/brown.

Visual Microscopy

Sporangiophores with ball-like sporangia; often branched.

Mycotoxins

Not a principal indoor mycotoxin genus.

Health Risks

Sinuses, lungs, brain: mucormycosis risk in immunocompromised individuals.

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Chaetomium Class A

Where it thrives

Paper, drywall, carpets, cupboards, roofs, wallpapers.

Visual ID

Cotton-like; white → grey → brown → black; often strong odor.

Visual Microscopy

Dark perithecia (globose→flask) with hair-like appendages.

Mycotoxins

Chaetoglobosins (cytochalasans) and related metabolites.

Health Risks

Irritant/allergenic; occasional skin/nail infections; exposure complaints include headaches, fatigue, airway irritation.

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Acremonium Class A

Where it thrives

HVAC systems, water-damaged interiors, carpets and wood.

Visual ID

Starts small & moist → becomes powdery; white, pink, orange, or gray.

Visual Microscopy

Septate hyphae; delicate awl-shaped structures from substrate or aerial hyphae.

Mycotoxins

No major indoor mycotoxin profile; main concern is opportunistic infection after trauma.

Health Risks

Eye/skin/lungs involvement in susceptible hosts; otherwise mainly allergenic/irritant.

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Alternaria Class B

Where it thrives

Carpets, textiles, wet bathrooms and under-sink cabinets; also HVAC.

Visual ID

Velvety dark green/brown colonies.

Visual Microscopy

Septate hyphae; brown conidiophores with zig-zag pattern.

Mycotoxins

Alternariol (AOH), AME, tenuazonic acid (TeA); mostly food-borne concern.

Health Risks

Potent aeroallergen tied to asthma sensitization/exacerbations; rhinitis, wheeze, eye irritation.

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Aureobasidium Class B

Where it thrives

Wet wood/window frames; deteriorating paints; dust on floors/mattresses; damp walls; humidifier water.

Visual ID

Pink, brown, or black colonies; reverse pale or black.

Visual Microscopy

Dark multicellular, branching elements; septate hyphae; cells cylindrical/oval/spherical.

Mycotoxins

Not a principal indoor mycotoxin genus; effects largely immune-mediated.

Health Risks

Associated with hypersensitivity pneumonitis (“humidifier lung”); worsens rhinitis/asthma in sensitized individuals.

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Cladosporium Class B

Where it thrives

Bathrooms (high RH), HVAC systems, sheetrock/subfloor, carpets, fabrics, OSB/plywood.

Visual ID

Olive-green/brown, suede-textured colonies.

Visual Microscopy

Dark, branching, septate hyphae; abundant airborne spores.

Mycotoxins

Not a leading indoor mycotoxin genus; main concern is allergen burden.

Health Risks

Eyes & airways allergy/asthma morbidity (itchy eyes, rhinitis, wheeze).

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Eurotium Class C

Where it thrives

HVAC units, floors, carpets/mattresses, hospital air, clothing/shoes, building materials.

Visual ID

Moderately rapid; downy → powdery; yellow to dull/blue-green.

Visual Microscopy

Teleomorph related to some Aspergillus; resembles Aspergillus heads in culture.

Mycotoxins

Flavoglaucin, auroglaucin, (neo)echinulins (strain/condition dependent).

Health Risks

Generally allergenic; can contribute to Aspergillus-related airway disease in susceptible occupants.

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Fusarium Class A Class B

Where it thrives

Carpets/mattress dust, damp walls, wallpaper, PU foams, humidifier pans, stagnant HVAC water.

Visual ID

Flat → woolly/cottony; white/tan/salmon/cinnamon/yellow/red/violet/pink/purple.

Visual Microscopy

Hyaline septate hyphae; short conidiophores; curved/fusiform ~3-septate spores.

Mycotoxins

Trichothecenes (DON, T-2/HT-2), fumonisins, zearalenone (primarily food hazards).

Health Risks

Eyes/skin/airways/GI; keratitis/skin infections after trauma; inhalation indoors mostly allergenic/irritant; ingestion causes GI/systemic toxicity.

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Stachybotrys Class A

Where it thrives

Wet cellulose (wood, cardboard, paper, hay, wicker) with prolonged dampness.

Visual ID

Typically black; may appear dark green/white/pink/orange; colonies powdery and damp.

Visual Microscopy

Septate hyphae; dark, flask-shaped conidia clustered at conidiophore tips.

Mycotoxins

Macrocyclic trichothecenes (satratoxins) and atranones; production depends on substrate and moisture.

Health Risks

Strong irritant/allergen; symptoms include cough, throat/eye irritation, headache, fatigue; invasive infection is rare.

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Ulocladium Class B

Where it thrives

Extreme water damage (kitchens/bathrooms), condensation areas, paper/textiles, wicker/straw, tapestries.

Visual ID

Black/brown → olive-black/greyish; textures suede-like → woolly/cottony.

Visual Microscopy

Multicelled conidia from geniculate, sympodially elongating conidiophores.

Mycotoxins

Not a principal indoor mycotoxin genus; key concern is allergenic exposure.

Health Risks

Allergic rhinitis/asthma in sensitized occupants; local irritation possible.

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Compact Differential Microscopy (Genus Cues)

Genus Key Cue
PenicilliumPhialides → basipetal conidial chains; brush (“penicillus”).
AspergillusConidial head + vesicle shape; hyphae/spore morphology.
TrichodermaWhite wool with green patches; hyaline phialides.
MucorSporangiophores with ball-like sporangia; often branched.
ChaetomiumDark perithecia with hair-like appendages.
AcremoniumDelicate awl-shaped structures from substrate/aerial hyphae.
AlternariaBrown, zig-zag conidiophores.
AureobasidiumDark multicellular branching elements; septate hyphae.
CladosporiumDark, branching, septate hyphae.
EurotiumTeleomorph of some Aspergillus; yellow/green downy→powdery colonies.
FusariumCurved/fusiform ~3-septate spores; hyaline septate hyphae.
StachybotrysDark flask-shaped conidia in clusters.
UlocladiumMulticelled conidia from geniculate, sympodial conidiophores.