Iam walking with a woman named Kerry, whom I have just met, to her car. She is in her mid-30s and has a tinge of attitude. When we reach her car, she opens the boot. Inside are hundreds of industrial-sized tubs of hummus, enough to power Brighton for a week. I met Kerry online, not via some kind of hummus-appreciation society messageboard, but on Olio, an app that is attempting to end food waste...