Cats eating dogfood?

After a recent diet change for the furry friends residing at the Smith Animal House, I found our cats rejecting their catfood and caught them eating from the dog dishes! They are all being fed the same brand, only their nutritional value was for the significant age and/or species we were trying to feed. I picked up Avoderm for Cats, Avoderm for Puppies and Avoderm for Adult Dogs. Unsure about the differences in nutritional requirements for Felines vs. Canines, I decided I needed to find out whether or not it really mattered. When I visited PetEducation.com they state that "... it is important to realize a cat's nutritional requirements are much different than those of a dog. For example, cats require higher levels of protein than dogs. Cats must have the amino acid called 'taurine' in their diet; dogs can actually make their own taurine. A cat eating food deficient in taurine can develop severe heart disease and other health problems. Almost all cat foods now contain added taurine. Cats require a different form of Vitamin A than dogs do. Dogs can use beta-carotene as a source of Vitamin A; cats cannot. Cats can not manufacture the fatty acid called 'arachidonic acid' and must have it supplemented in their diet; it is not essential for dogs to have this fatty acid in their food." But this still didn't answer my question of whether or not it would be harmful if the cats ate dog food without my knowledge, so I proceeded to PMI Nutrition and they state "...Stealing a bit of one another’s food occasionally is not going to harm your pet but in order to meet the specific day to day nutritional needs, a diet formulated for their own species should be fed." Therefore, I can either starve my cats or change their food again, if they don't begin eating what I've put in front of them because they are GOING TO EAT CAT FOOD, whether they want to or not! The only thing is that now I have another question. Where did cats get taurine BEFORE manufactured catfood came to be??