Fungi are a type of organism that includes the mushrooms we eat. But there are much tinier fungi that are part of some foods. These microscopic forms of fungi are known as microfungi.
Food invaders
First, let’s look at some microfungi that are invaders. Fungi spread through their food source with threads called hyphae. And their food source may well be your food source!
Fungi feed on living things and organic matter (things that were once alive or come from living things). As they do so, they break down their food by releasing chemicals into it.
Moldy bread
Mold is a type of fungus that invades food and breaks it down, causing it to spoil. If you look at a slice of bread and see a patch of mold, you are actually seeing a fungus feeding on the bread. The mold is a network of hyphae called a mycelium.
As the mycelium spreads, the hyphae grow fruiting bodies that hold spores, which are like tiny seeds. When the fruiting bodies release the spores, they travel in the air to find new food to grow on.
Making bread
Yeasts are different from regular fungi. They only have one cell. Carbohydrates—sugar and starch—are the yeast cell’s favorite food. When yeast is mixed with flour and water to make bread, the yeast cells begin to feed on the starch in the flour. This process, called fermentation, releases carbon dioxide bubbles. The bubbles make the bread swell up, or rise. After the bread is cooked, the bubbles appear as holes.
You can see the holes in this bread made by the yeast releasing gas bubbles.
These yeast cells are budding to reproduce themselves. The bud comes off to make a new yeast cell. These cells have been magnified 4,000 times.
How Small Is Small?
An average yeast cell is about 4 micrometers across. There are 1,000 micrometers in a millimeter, so you could line up 250 yeast cells alongside just 1 millimeter on your ruler. You could fit more than 6,000 alongside 1 inch.
