Serratia

• The air and surfaces around you are home to multitudes of bacteria, fungi, viruses, mites, algae and protozoa.
• A lot of this fungal growth is what we call mould.
• But what do the myriad colours that appear on our stuff tell us about the world we try not to think about?

Black

• The concept of toxic black mould is one many people have become aware of due to flood impacts.
• Stachybotrys is the one known as toxic black mould.
• When the grout in your shower turns black though, that’s a different fungus called Aureobasidium.

Blue

• That blue orange I mentioned before, you can thank Penicillium for that.
• The organism that gives us blue cheese and the antibiotic penicillin is also responsible for producing a dense growth of mould that almost looks like smoke when disturbed, spreading millions of spores onto the rest of your fruit bowl.

Yellow and orange

• In fact, some need exposure to light – and ultraviolet (UV) light in particular – to complete their life cycle.
• They produce a spectrum of staining that can often turn damp items yellow, brown or orange.

Green

• We’re all fairly familiar with the green spots that turn up on mouldy bread, cake and other food items.
• The green tuft is often from a group of fungi called Aspergillus.
• In the green gang is also a fungus called Trichoderma, which is Latin for “hairy skin”.

Pink, purple and red

• Neurospora, also known as the red bread mould, is one of the most studied fungi in scientific literature.
• It’s another common, non-hazardous one that has been used as a model organism to observe fungal genetics, evolution and growth.
• Fusarium is less common indoors, being an important crop pathogen, but will sometimes turn spoiled rice purple.

White

• One of these was hyaline and non-hyaline, essentially referring to transparent and coloured, respectively.
• This fungus is a parasite of some moths and cicadas and is visible as brilliant white, tree-shaped growths on their unfortunate hosts.