How to Identify Aspergillus Niger

Aspergillus niger, more commonly known as black mold, is a fairly common fungus with an extremely bad and well-earned reputation. This mold is a member of the fungal genus Aspregillus ("niger" being Latin for black), and can be responsible for a number of respiratory problems in the lungs, bronchus, sinus and ears. Fungal ear and lung infections are the the most common manifestation of Aspergullus exposure; infections are most likely to strike those with preexisting immunological disorders.

Things you'll need:

• Mold-spore-rated dust mask and ear plugs
• 5x-magnification magnifying glass
• Microscope and glass sample plates

Instructions

STEP 1

Identify the colonies visually. The mold you see with the naked eye is actually a colony of thousands of microscopic mushrooms. These colonies can range in size from a single mold spore to acres across, but are generally broken up into distinct patches and spots. A wall or flat surface infested with black mold will usually look as though it's been hit with a load of 20-gauge bird shot, peppered with countless yellow-black spots about the size of a pinhead. These spots will eventually coalesce to form a single black mass, but the outer parts will remain peppered.

STEP 2

Strap your mold mask on and put your ear plugs in and examine one of the individual colonies (spots) with a magnifying glass. The entire colony will look a bit "pixelated," made up of millions of tiny spots like one of Seurat's pointillist paintings. Under five to 10 times magnification, the individual spots will appear deep red-black in the center where the spore heads are the thickest. At its edges, the colony changes to yellow or white, depending on the specific strain of Aspergillus and the substrate.

STEP 3

Take a sample, put it on a glass sample slide and examine it under a microscope. Increase magnification until you can see the individual fungi. The individual Aspergillus fungi look like dandelions, with a transparent yellowish stem (called the metulae) that supports a dark red-brown head shot through with black lines (called the phialides), which radiate out from the center. On the tip of each phialide you'll find a transparent, yellowish-red, spherical spore.

Read More:

Classification of Aspergillus Niger
Aspergillus niger