http://www.fda.gov/oc/opacom/hottopics/petfood.html

Hope it’s ok to post links here. If not, my bad.

http://www.dogfoodproject.com/index.php?page=labelinfo101

here is a link to an excert for the book.
http://www.homevet.com/petcare/foodbook.html

If you don’t want to go to the link just read this small excert below to understand what can be in some of the foods that marketing makes you think you can trust.

“As discussed in Chapter Two, companion animals from clinics, pounds, and shelters can and are being rendered and used as sources of protein in pet food. Dead-stock removal operations play a major role in the pet food industry. Dead animals, road kill that cannot be buried at roadside, and in some cases, zoo animals, are picked up by these dead stock operations. When an animal dies in the field or is killed due to illness or disability, the dead stock operators pick them up and truck them to the receiving plant. There the dead animal is salvaged for meat or, depending on the state of decomposition, delivered to a rendering plant. At the receiving plants, the animals of value are skinned and viscera removed. Hides of cattle and calves are sold for tanning. The usable meat is removed from the carcass, and covered in charcoal to prevent it from being used for human consumption. Then the meat is frozen, and sold as animal food, which includes pet food….

At the rendering plant, slaughterhouse material, restaurant and supermarket refuse, dead stock, road kill, and euthanized companion animals are dumped into huge containers. A machine slowly grinds the entire mess. After it is chipped or shredded, it is cooked at temperatures of between 220 degrees F. and 270 degrees F. (104.4 to 132.2 degrees C.) for twenty minutes to one hour. The grease or tallow rises to the top, where it is removed from the mixture. This is the source of animal fat in most pet foods. The remaining material, the raw, is then put into a press where the moisture is squeezed out. We now have meat and bone meal.”