Neat tidbit, before chicken wings became a popular food item in the 1980s, chicken wings were considered scrap meat, like the necks. At the time, the rumors that McDonalds threw an entire chicken into a grinder and used that slurry in the nuggets was more or less true. Fairly recently, those scrap meats have become more expensive than chicken breasts, so now you will see all of the fast food commercials proudly boasting that their products are made with 100% sliced chicken breast, or white meat chicken, but in reality, thats because its more expensive to feed consumers that chicken that was thrown through the grinder. So just remember, they didn't improve their food quality because they found it was in the consumers best interest, it just became cheaper and more advertising friendly to feed people the people food.
It's worse than that. The reason mechanically separated meat is more expensive now is that they're no longer allowed to throw the whole carcass into the grinder, due to the risk of disease. Instead, they now throw in just the breast and call it "100% chicken breast", as though they're doing something different, when it's exactly the same process only with fewer parts of the animal.
Well except Tacobell. Going off on a tangent here, but Tacobell is an amusing creature. They use Grade D meat in their taco meat, meaning that it is just barely safe for humans to eat. However there have been some new large brand dog foods, that are now using Grade C meat, granted it is a more expensive dog food, but it is dog food that you can find at big retailers, not some specialty shop for nutjobs that spend more on dog food than they do on their mortgage/rent. So next time you are sitting with your dog, eating a taco from tacobell, just think, he may be looking up at you, judging you... before walking off to lick his crotch.
That's not true at all. USDA beef grades simply refer to the age of the beast when it was slaughtered, nothing more. Grade D means it was 6-8 years old, Grade C is 3.5-6 years, and so on. It's all equally safe (or not, depending on your point of view) for human consumption. Dog meat typically isn't graded at all, and in most cases can't even be legally identified as "meat", thanks to such tasty ingredients as "meat byproducts" (bone, hooves, fur, and other "non-meat" parts of the animal) and "meat meal" (recycled roadkill, zoo animals, diseased livestock, former pets - yes, your dog is quite possibly a cannibal).
