A type of fungi, molds are nature’s garbage collectors, and they tend to show up everywhere. The air around you contain millions of microscopic spores, which are seeds from fungi – similar in function to dandelion seeds. But the spores can only grow and become mushrooms if the growth conditions are right. The best growth conditions are damp houses and old food. But mold is not only damaging. In fact, it can also be used to produce life-saving medicine.
What are molds?
Molds can be very beautiful and are found in an abundance of different colors: green, blue, yellow, red or pink. The colors are due to the many substances that the fungi produce, and which are used for everything from protecting them against the sun’s rays to keeping other fungi at bay.
Sometimes molds create small, fine drops of exudate on their surface. These drops can make them appear wet and contain a very high concentration of enzymes and secondary metabolites, which are substances that are important for the survival of the molds.
In contrast to common mushroom-shaped fungi, as you know them, molds grow by forming a large mycelial network from which so-called conidia grow. Conidia are microscopic spore-bearing outgrowths. These millions of small branches with spores give molds a dusty appearance; conidia actually means “dust” in Greek.
Molds, the good and the bad
You may be most familiar with molds as the harmful fungus that can be found in the house. But in reality, molds can be much more than that. Read on and learn about why molds are so important — and can be so harmful.
Experiment: Grow mold on different types of food
Try leaving out a piece of bread, a lemon, a garlic and a tomato and see whether any mold grows on them. This will allow you to study the shapes, colors and textures of different molds.
If you want to go further, test organic versus non-organic food samples or place them in damp versus dry conditions.
Important: Remember to cover the foods if you see mold to avoid the fungi spreading.
You will no doubt have experienced the same thing when your bread has lain in a cupboard for a couple of days and has become moldy. It has been attacked by molds, which break down the starch in the bread. It is not enough just to cut away the moldy area as the mold sends out hyphae through the bread and these go further than one can actually see.
It is relatively easy to identify what mushrooms are growing on citrus fruit. It is the green Penicillium digitatum and the blue Penicillium italicum in particular which attack citrus fruit. Both fungi cause a lot of harm to citrus harvests every year!
Garlic actually has antifungal properties, which means that it inhibits mushroom growth. Therefore, like chili and ginger, it is used a great deal in countries where food hygiene standards are relatively low. But certain molds, for example, the green Penicillium hirsutum, have specialized in growing on garlic.
If you are lucky, zygomycetes will start to grow on your discarded tomatoes. Zygomycetes make up one of the five fungal phyli. They are easy to spot as their spores grow into a sort of thin cilia with a small bobble on the top.
See what happens when you use the following types of foods:
Organic vs. non-organic
Try and see what happens if you leave out both organic foods and foods which have been sprayed, at the same time. On which do you think fungal growth would occur first, and why?
Damp vs. dry
Try to experiment with dampening your foods before you lay them out, to see how this affects how long it is before mold appears. As already mentioned, molds love to grow in damp places. So perhaps you understand now why damp cellars so often contain molds.
Don’t forget to take pictures to document the mold growth on your foods. Make a mold collage.