Breakfast cereal he launched the Cornflakes brand, which overnight captured a national market. Soon there were forty rival manufacturers in the Battle Creek area. His brother William K. Kellogg (1860–1951) worked for him for many years until, in 1906, he broke away, bought the rights to Cornflakes, and set up the Kellogg Toasted Corn Flake Company. William Kellogg discarded the health food concept, opting for heavy advertising and commercial taste appeal. Later, his signature on every package became the company trademark. The second major innovator in the cereal industry was Charles W. Post, a salesman who was admitted to Kellogg's sanitarium as
John Harvey Kellogg problems with James Caleb Jackson who already sold a wheat cereal under that name. In 1881, under threat of a lawsuit by Jackson, Kellogg changed the Sanitarium cereal's name to "Granola". It was used initially by patients at the Sanitarium, but slowly began to build up a following among former patients. In 1890, John formed the Sanitas Food Company to develop and market food products. The Kelloggs are best known for the invention of the famous breakfast cereal corn flakes. The development of the flaked cereal in 1894 has been variously described by those involved: Ella Eaton Kellogg, John Harvey