If the advertisements are to be believed, only the best is good enough for our pets. But instead of getting balanced nutrition our four-legged friends are being offered an unhealthy mix of slaughterhouse waste, diluents and stabilisers. Then there are other scandalous revelations: the addition of sewage sludge, for example. Or innovative ingredients created by natural gas with the help of bacteria. With no labelling, of course. To make it acceptable to animals, flavourings are then added to the mix. Hans-Ulrich Grimm lifts the lid on the unappetising truth about commercial pet food.