Pasteurized dried egg whites can be used where egg whites are needed; follow package directions for reconstituting them. Unlike raw egg whites, which must be thoroughly cooked before serving to kill harmful bacteria, pasteurized dried egg whites can be used in recipes that do not call for egg whites to be thoroughly cooked. Keep in mind that meringue powder may not be substituted, as it has added sugar and starch. Find dried egg whites in powdered form in the baking aisle of many supermarkets and through mail-order sources.