During the processing, eggshells, intestines, feet, leg scales, and other parts not fit for human food – including condemned and inedible materials and, sometimes, waste – are processed using denaturing and rendering to turn out an "edible" product used in most pet foods.
The Food and Drug Administration say byproduct meals are "safe" for pets, but pet parents often choose not to feed their beloved pets anything that they themselves wouldn't eat.
Purina hired Windsor Laboratories to test the Blue Buffalo food, and James V. Makowski did the testing on different Blue Buffalo pet food varieties.
Dr. Makowski concluded that many of the Blue Buffalo pet food bags contained poultry byproduct meal, and that Blue Buffalo's grain free pet food contained grains -- again, contrary to its labeling.
Blue Buffalo did not have its pet food tested to verify or refute the results, presumably because of its own admission that it tests all of the Blue food already, and the Blue Buffalo ingredient list does not list chicken byproduct.
Blue Buffalo sprung for its own expert, Vinayak P. Dravid, PhD, to opine on the testing procedure Dr. Makowski used.
According to "Section 49, Conclusion" of the report, titled "Declaration of Vinayak P. Dravid, Ph.D.," Dravid states that "Dr. Makowski's report is so lacking in detail and documentation that it fails to provide a basis for his conclusions."
In its commercials and other marketing, Blue Buffalo demonizes any pet food supplier that uses byproduct meal in its pet foods, and because Blue Buffalo claimed not to use byproduct meals, the company's pet foods became quite popular.