To make tacos for 20 people, purchase 7 1/2 to 8 1/2 pounds of raw beef to make approximately 6 ounces of cooked beef per guest. Also, buy 6 1/4 to 7 1/2 pounds of boneless chicken to provide 4 to 5 ounces of cooked poultry per guest.
Tacos are made with beef, pork, chicken, vegetables, shrimp or fish. The standard taco uses 2 ounces of meat. Tacos are typically topped with diced tomatoes, lettuce, cilantro, diced onions, shredded cheese, sour cream, salsa and guacamole. An average serving of Mexican rice is 1 1/2 to 2 ounces per guest, and a serving of beans is 2 ounces per guest.