A sausage is a food usually made from ground meat with a skin around it, so beef sausages are stuffed with only beef. Typically, a sausage is formed in a casing traditionally made from intestine, but sometimes synthetic (Wikipedia, nd).
An allergic reaction to beef sausage may occur if the person is allergic to anything it is made with, including, but not limited to: beef, natural casing, fillers in the product, and soy. Mild to severe allergic reactions may occur, and if they happen, you should seek medical attention.
Sausage making is a traditional food preservation technique. Sausages may be preserved by curing, drying, or smoking. They can be eaten by themselves or mixed into a food dish (Wikipedia, nd).
Information from Nutrition Data