Cyril P. Callister called Vegemite, first sold by Fred Walker & Co in 1923. Working from the details of a James L. Kraft patent, Callister was successful in producing processed cheese. The Walker Company negotiated a deal for the rights to manufacture the product, and in 1926, the Kraft Walker Cheese Company Ltd was established. Callister was appointed chief scientist and production superintendent of the new company. Between 1919 and 1927 he had 3 children (two boys and a girl) named Ian, Bill and Jean. They were the original vegemite kids. During World War II Ian unfortunately died Callister got his Doctorate from
Cyril P. Callister was withdrawn from active service on the order of the Minister for Defence and assigned to the Munitions Branch, making explosives in Britain. Following the end of World War I, he married Scottish girl Katherine Hope Mundell and returned to Australia and resumed employment with Lewis & Whitty in 1919. In the early 1920s, Callister was employed by Fred Walker and given the task of developing a yeast extract, as imports from the United Kingdom of Marmite had been disrupted in the aftermath of World War I. He experimented on spent brewer's yeast and independently developed what came to be