Excerpts from two different sources:
Feeding raw Meat
Dogs are carnivores, and evolved eating raw meat. The consumption of cooked flesh is totally and completely unnatural for them. They do not get optimum nutrition from it, it is not well digested by them, and it not what their organs were designed to process. Eating a raw diet, based on the evolutionary diet of the dog, will make the animal healthier. This healthier animal will be able to handle a certain amount of bacteria in its food, and will be resistant to most disease-causing microorganisms it encounters.
Further, dogs are not just predators but scavengers, and evolved eating rotten and decaying flesh, as well as the droppings of herbivores and even other carnivores. They can handle bacterial loads that would kill us, without blinking an eye.
What is a Carnivorous Mammal?
Carnivores, very simply, are meat eaters. They separated from their ancestors, the plant eaters, a hundred million years ago, and have since developed into the animals we know today. They have specialized "equipment" that allows them to capture prey, and eat it. Long claws on bears, extreme dexterity in raccoons, and long distance communication in wolves are but a few unique characteristics.
The dental arsenal of carnivores is truly impressive. Large pointed canine--fang--teeth extend into the skull and jaw bones equally as far as they stick out. They are designed to grasp and tear their prey, a job that is essential to their survival. Massive molars crush bones and premolars slice through sinew. The carnivores teeth, doubled with powerful jaw muscles, are a deadly combination.
Because the meat eaters may go for extended time periods before another meal is located and killed, they have developed a digestive system to compensate. A carnivore's stomach is large and very simple, useful for food storage, digestion, and absorption. Flesh is highly digestible, thus the animal can gorge itself, wait two hours, then come back and do it again. This can be continued until the downed game is completely gone, at which time the carnivore will be completely "recharged" and ready to fast until the next meal can be obtained.