Picked beef is a type of food that is made by curing and salting beef. It is usually served cold and is often used in sandwiches or salads. The term 'picked beef' is derived from the process of curing and salting the beef, which is known as 'picking.' NIT is an acronym for nitrate, which is a salt compound that is used in the curing process. Nitrates help to preserve the beef and give it its distinctive flavor.