- Udder: The fatty white meat of the mammary glands of milking animals such as cows, sheep and goats which is cooked and sliced. Once popular but now rarely available. Occasionally used as a pasta stuffing.
- Unbleached flour: Flour which has not been treated with a bleaching agent to whiten the color.
- Ultra-heat treated: (A liquid) which has been rapidly heated to 132°C, held at this temperature for 1 to 2 seconds (up to 6 minutes for some products), then rapidly cooled, generally in a stainless steel plate heat exchanger through which the liquid flows as a very thin film. This treatment sterilizes the liquid without too much change in its flavour.
- Uncooked curd: Curd for cheese making which has not been heated to more than 40°C
- Unleavened: Without any natural or chemical raising agent.
- Unleavened bread: Bread made from flour, water and salt without using a raising agent or incorporating air.
- Unna coffee: East Africa The traditional coffee of Ethiopia which is roasted, ground and brewed at the table.
- Unpolished rice: Rice from which the bran and most of the germ has been removed.
- Unsweetened chocolate: Chocolate containing no sugar, used for baking.
- Upside down cake: A cake baked in a tin with a decorative layer of fruit on the bottom so that when it is turned out the fruit will be on top.
- Udon: A thick Japanese wheat flour noodle usually served in soup.
- Umeboshi plum: Japanese apricot colored with red shiso leaves and pickled in salt with a sour and salty taste often served as a digestive.
- Univalve: A mollusk with a single shell, such as abalone.
- Unsaturated Fat: A fat that is normally liquid at room temperature.