Various types of seasoned ground meat are enclosed in a casing (originally made from intestine, now some are synthetic). Traditionally, sausage makers would include scrapes such as edible tissues and organs that they wouldn't otherwise sell.
There are many different types of sausage. Many are made from pork or beef. Some are made from chicken or turkey. There are even soy sausages made without meat. Those made from pork or beef often use...
You will find sausages made from any meat you can imagine. Some even include grains like rice or wheat. Most are made from either pork or beef. All include some type of seasoning.
Sausage is made at different meat processing plants throughout the country. Spices are added through the processing process giving meat its delicious distinct flavor.