Mission Foods is the world's largest manufacturer of corn and flour tortillas, producing over 25% of the tortillas sold in the world today. The company was founded in 1949 and is now a subsidiary of Gruma S.A. of Mexico City.
Its tortillas are used exclusively at the Disneyland Resort, and can be found at most supermarkets in the United States as they distribute products to more than 30,000 stores nationally. The company generally has an annual sales figure somewhere upwards of $600 million from its tortilla sales.
Mission seems to be fanatical about the freshness of their tortillas. According to a magazine article, Mission's goal is to have its tortillas delivered (not just shipped) within 24 hours of baking. At its 150,000 sq ft Dallas distribution center Mission delivers its tortillas at a rate of 700 cases/hr.
Gruma Corporation produces its tortillas and other products at several manufacturing facilities located primarily in large population centers, mainly in Western and Southwestern United States. Additionally, a plant was built in England in 1999 to penetrate the European tortilla market.
Sources:
Modern Materials Handling. Boston: Mid-Oct 2000. Vol. 55, Iss. 12; pg. 77, 1 pgs
http://www.gruma.com/Documentos/seccion_7/Categoria_124/Disney%20Press%20Release.pdf
http://www.gruma.com/vIng/NuestrasEmp/nuestras_empresas-grumacorp.asp