Rick Moulton, age 7, of Montgomery, Alabama, for his question:
What makes bread go moldy?
This moldy story is about plants. The grubby patch of mold on the bred is really a growing garden. The tiny plants are not very much like dandelions or daffodils. Molds do not have real roots, or flowers or leafy greenery. Instead of seeds, they have dusty little spores. The spore that starts a patch of mold is too small for our eyes to see. This is why the moldy patch seems to come from nowhere.
Most molds grow outdoors. They help to make the moist soil richer for all the other plants. But a few molds get indoors and spoil our food. All the hundreds of different molds are miniature cousins of the mushrooms. Other plants have green chlorophyll to make their own food. But molds and mushrooms are fungus plants. They cannot make their own food because they have no chlorophyll. This is why they need special diets such as a nice slice of our bread.
A grubby patch of mold is a growing mold plant. When it gets ready to multiply, it grows a whole army of tiny spores. These dusty midgets are too small for our eyes to see. They float around in the air and we never know when they come into the kitchen. The spores are supposed to settle down and start multiplying into more mold plants. But they can grow only in certain places.
Once in a while, a lucky spore lands on just the right spot. It must be moist and fairly warm and there must be plenty of the right food. Molds need the foods that other plants make for themselves. Green plants always stuff their most nourishing food into their seeds. Bread, as we know, is made mostly from wheat seeds. This is why molds like it.
Suppose we leave a slice of bread on the kitchen counter. We cannot see the tiny mold spores drifting around in the air. But sooner or later one of them lands on the bread. It nestles down into the spongy pores, where things are moist and warm. Then it pokes down hungry little fingers and begins to soak up nourishment. Soon it grows a topping and we see a moldy patch of grubby greys and greens. The moldy bread is ruined and we must put in out with the garbage.
If we let it stay there in the kitchen, the mold plant has time to multiply. In a day or so, it grows a new flock of tiny spores. Off they go, sailing around in the air. Some of them will land on other food. But we cannot see them until they start growing their moldy patches.
Midget mold spores are drifting around in the air all the time. Most of them are outdoors, but we cannot keep them out of the house. They get into the cleanest kitchens. Sometimes we bring them in with the groceries. This is no reason to worry. Most mold spores do us no harm because our bodies are used to them. But we cannot eat moldy bread and we should not let moldy patches thrive anywhere indoors.