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.
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.
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).
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.
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.
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.
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.
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.
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.
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).
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.
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.
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.
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.
Compact Differential Microscopy (Genus Cues)
| Genus | Key Cue |
|---|---|
| Penicillium | Phialides → basipetal conidial chains; brush (“penicillus”). |
| Aspergillus | Conidial head + vesicle shape; hyphae/spore morphology. |
| Trichoderma | White wool with green patches; hyaline phialides. |
| Mucor | Sporangiophores with ball-like sporangia; often branched. |
| Chaetomium | Dark perithecia with hair-like appendages. |
| Acremonium | Delicate awl-shaped structures from substrate/aerial hyphae. |
| Alternaria | Brown, zig-zag conidiophores. |
| Aureobasidium | Dark multicellular branching elements; septate hyphae. |
| Cladosporium | Dark, branching, septate hyphae. |
| Eurotium | Teleomorph of some Aspergillus; yellow/green downy→powdery colonies. |
| Fusarium | Curved/fusiform ~3-septate spores; hyaline septate hyphae. |
| Stachybotrys | Dark flask-shaped conidia in clusters. |
| Ulocladium | Multicelled conidia from geniculate, sympodial conidiophores. |
