Much has been made lately of "pink slime," the "lean, finely textured beef" product that in the last month has been given the boot by everyone from McDonald's to public schools. But pink slime is not the only meat product out there with a less-than-appetizing genesis. Y'all ready for "white slime" and "advanced meat recovery?" ProPublica has a good rundown of the other two big meat "products" you probably have eaten and, well, we hope you finished your lunch already. Because yes, we have videos.

Mechanically Separated Meat

So you've got some extra animal carcasses around, what to do? Rather than make a good stock, many big meat companies simply drop the bodies into a high-pressure sieve which separates bone from edible tissue and then spits out a paste ("white slime"). That paste can then be added to other processed meats. By law, when used, it must be labeled as "mechanically separated" pork, chicken, lamb, or turkey (since 2004 you can't use beef for the process out of fear of diseases). If you are curious, there are lots of rules about exactly what the final product can be made of ("The product resulting from the separating process shall not have a calcium content exceeding 0.75 percent, as a measure of a bone solids content of not more than 3 percent"). Hot dogs, anyone?

Advanced Meat Recovery

Or, instead of dumping the carcasses in a sieve, you can scrape, shave or press meat off of the bones. If done properly, manufacturers can get "meat" they can then add to "ground" meat packages. Meat gotten through this method doesn't require any special label. However, if done improperly (by getting too much bone off with the machinery) then that meat has to be listed as "mechanically separated." The cut off for that is 150 mg of calcium per 100 grams. Ground beef tacos, anyone?

And thus we end today's lesson here at Bovine University.