"Every so often an event occurs that shakes the industry to its core. Amazon's acquisition of Whole Foods is one of those." So said one US retail analyst today after the e-commerce giant announced a deal to buy the natural and organic grocer for US$13.7bn. The transaction stunned the sector, with analysts hailing it a game-changer. Amazon faces short-term challenges with Whole Foods but the acquisition looks set to give its ambitions in grocery - a sector it entered ten years ago - a boost and rival retailers and manufacturers will be sitting up and taking notice. Dean Best reports.