Frozen egg products are often preferred as ingredients in certain food products. Salt, sugar, or corn syrup is normally added to yolks or whole eggs prior to freezing in order to prevent gelation or thickening of the products. Egg whites freeze well without any additives. Egg products are frozen at −23 °C (−9 °F) and are packed in different-sized pouches and waxed or plastic cartons. Products include egg whites, egg yolks, salted yolks, sugared yolks, salted whole eggs, sugared whole eggs, and various yolk and white blends with or without added sugar or salt. At frozen temperatures they have a shelf life of about one year.