Ginger is a root vegetable that can be found in fresh, powdered and candied variations. Fresh ginger root looks similar to a gnarled tree branch and has light brown skin. The flesh of the ginger is greenish yellow and fragrant. You can cut mold off the skin of the ginger and consume the flesh, provided the mold hasn't reached the flesh. Discard the ginger root if you have doubts about its safety.
Like other fruits and vegetables, ginger can become moldy if it gets wet, is not stored in a well-ventilated area or comes into contact with another moldy product. Mold can grow on the skin of the ginger root, often appearing white, gray or greenish and furry. You should refrain from buying moldy ginger, but if you notice that some ginger in your refrigerator has become moldy, it's not necessarily ruined.
Trim the skin off the ginger with a sharp paring knife and check the ginger flesh for mold. If the flesh is not moldy, taste the ginger to test whether it tastes as it should. If it's not moldy, it will have a sharp, ginger taste that feels like it's burning your mouth. If it's moldy, it will smell or taste like mildew, like any vegetable that has spoiled. Discard the piece of ginger root unless the mold only affects one area of the ginger. If the ginger tastes fine, carefully trim all the moldy skin off the flesh.
Eating a piece of ginger after it's had its moldy skin removed could give you a reaction if you have an allergy or sensitivity to mold. Discard the entire piece of ginger and buy a new one.
Choose ginger root that is free of mold and firm to the touch. The skin should be tight and smooth, rather than wrinkled. Store ginger in your refrigerator or freezer to extend its life. Don't peel it until you plan to use it and monitor it for mold occasionally. Unpeeled ginger has a typical shelf-life of three weeks in the fridge, or six months if stored in the freezer.