Cadbury used to be this country's most trusted brand. But things began to change when it admitted changing its recipe to use palm oil rather than cocoa butter. A clever marketing campaign by its local rival, Whittakers, saw that company dramatically increase its market share. Now the owner of Cadbury, Mondelez International, says it is closing its Dunedin factory and move production to Australia. The factory has produced Cadbury products at the site for 80 years. Auckland University of Technology marketing professor, Roger Marshall talks about how it has come to this.