Mold and Mildew

These are types of fungi; typically, mold is black or green, and mildew is gray or white. Mold tends to grows on food, whereas mildew grows on damp surfaces, like bathroom walls, basement walls, or fabrics.

Mold grows in the form of multicellular filaments or hyphae, while mildew has flat growth. Mildew is often referred to as a kind of mold and is classified as powdery (under the order Erysiphales) and downy (under the family Peronosporaceae).
Mildew is a specific kind of mold, usually with a flat growth habit. Mold is a fungi that contains multiple identical nuclei. It grows in the form of hyphae of filaments.
Mildew could be downy or powdery: Downy mildew starts as yellow spots that first become brighter in appearance and then the color changes to brown. Powdery mildew is whitish in color and that slowly turn yellowish brown and then black. Mold has a fuzzy appearance and can be an orange, green, black, brown, pink or purple in color and can be found in several shapes.
Some molds are used in food production, for example, Penicillium is used in the production of cheese, Neurospora in the production of oncom, which is made from the by-product of tofu.
To prevent mildew at home, keep all the areas moisture-free. There are mildew removers available at stores to eliminate mildew. To protect crops from mildew use mildew-resistant seeds, remove infested plants, avoid overhead heating.     To prevent mold in your home, you need to keep all the areas dry and moisture-free.
Prolonged exposure to mold spores can cause health problems such as allergic reactions and respiratory problems, due to the toxins (mycotoxins) it produces.

Mildew can cause damage to crops and other plants it infests. Inhalation of mildew can cause coughing, headache, scratchy throat and lung problems. Mildew can also start growing in lungs and cause other serious health problems.

Some molds are used in food production, in the production of bread, soya sauce and so on. Mildew has no uses as such in food production.