Supermarket Secrets, BBC One, review Gregg Wallace, the sweet-toothed MasterChef scoffer, was back last night with the latest in the Supermarket Secrets series (BBC One), this time explaining how the largest food retailers cope with our demands for 50 million Christmas meals. And another: all that Australian wine arrives in the UK in giant bags and is actually bottled here. Go on then, one more: the number one item we buy at Christmas is potatoes, number two is chocolate and number three mince pies. Wallace danced around from production line to brussels sprout farm, to salmon lake and on to a cake factory. To his credit, while he was nice to the supermarkets who had given him access, he didn't shy away from the hard question or statement, even if the answers were left unscrutinised. For example, at the salmon lake he said we were all confused about what was sustainable in fishing these days, and he later summed up simply and correctly: "Mass farming of fish like this has its critics but it's turned a luxury item into a cheaper food that more of us can enjoy." Some 90 per cent of our food comes from supermarkets in what Wallace said was "a staggering operation." It was good to have a presenter who looked convincingly staggered.