In a large mixing bowl, add beef, sausage, onion and bell pepper. Knead well until combined to avoid bites of only sausage or beef. You can use clean hands or use a pastry cutter to help combine them.
Add one egg and knead until fully combined.
Add tomato sauce and knead until fully combined.
Transfer meat mixture into an ungreased loaf pan. Press into pan to pack meat tightly. Level the top.