Limes are the most acidic of all citrus. Although lemons and limes may not be what you would choose for an afternoon snack, they are considered essentials when we want to bring out the flavor of other foods. Choose limes that are firm and heavy for their size, free of decay and mold. They should have a glossy skin that is deep green in color; although limes turn more yellow as they ripen. The greener their color - the more tart their flavor. Limes that are mostly brownish in color should be avoided since this may be an indication that they have "scald" which may cause them to have an undesirable moldy taste. Limes are a staple in the cuisines of Latin America, Southeast Asia, India, Africa and the West Indies. Limes have thin skin, few seeds and are an excellent source of vitamin C.