The natural outer covering or protective layer of an animal or plant. In animals this includes skin, shells, scales, and membranes; in plants it covers seed coats, fruit rinds, husks, and the skins of vegetables. The integument shields the inner tissues from physical damage, water loss, microbial invasion, and pests. In food science, the properties of the integument matter greatly: the waxy skin of an apple controls moisture loss, the husk of grain must be removed during milling, and the shell of an egg provides a barrier against contamination. Processing techniques such as peeling, dehulling, and waxing all interact with the integument to improve safety, appearance, and shelf life.