A marinade is a seasoned liquid, usually an acidic ingredient such as vinegar, citrus juice, wine, or yogurt combined with oil, herbs, and spices, used to flavor and partially tenderize meat, poultry, seafood, or vegetables before cooking. Its acid and enzymes act on the surface of the food; they tenderize only the outer layer, not the interior, since they penetrate no more than a few millimeters. A marinade is the liquid itself, distinct from marinating, the act of soaking food in it. Common styles range from soy sauce, garlic, and ginger blends in East Asian cooking to olive oil, lemon juice, and oregano combinations in Mediterranean cooking. Because marinade has touched raw food, leftover marinade should be discarded or boiled before reuse as a sauce.