Zucchini should have a bright green, glossy skin on the outside. When cut open, the inside should be creamy white or yellowish in color. The texture of the flesh should be firm but tender, and it shouldn't have any brown spots or discoloration. If the zucchini is overripe, it will become soft and mushy on the inside. When selecting zucchini at the store, look for ones that are heavy for their size and have no blemishes or bruises on them. Avoid any zucchinis that are too soft or have a dull appearance to them; these will be past their prime. If you plan to use your zucchini within a few days of purchase, you can store it in the refrigerator; otherwise, store it in a cool, dry place out of direct sunlight.