True mystery meat...  

I'm not a  big fan of the McRib.  It's too messy, especially for the road and the texture defies mouth analysis. But I'm far from being it's biggest critic.

Some point to the lengthy list of unappetizing ingredients. But hey - what prepared food or restaurant fare doesn't read like that?

The more unsettling accounts are how the umm, meat is processed.

Roger Mandigo is an emeritus University of Nebraska animal science professor credited with the technology that made the McRib possible. And here's its story, straight from the meat scientist's mouth.

Roger Mandigo earned induction into the Meat Industry Hall of Fame for his invention of "restructured meats."

Back in the 1970s, Mandigo tells The Salt, he was approached by the National Pork Producers Council (the folks who later brought you "the other white meat") to create a product with pork trimmings that could be sold to the fast food giant.
"The pork producers wanted to see more pork on the menu, and they were targeting McDonald's," Mandigo said.
Mandigo went to work in the lab and came up with a new take on an old-fashioned technology: sausage-making. Instead of just stuffing pork meat inside a casing, Mandigo used salt to extract proteins from the muscle. Those proteins become an emulsifier "to hold all the little pieces of meat together," he says.
"All we did was reuse the technology that had been around for hundreds of years and emphasize that we could shape products to shapes people wanted," he says.
And here is where our story takes an interesting twist: Seems the McRib was not born in the shape of its current pork patty. The original concoction Mandigo made was formed as a faux pork chop.
McChop? Maybe not.
"[McDonald's] chose the shape," Mandigo said. "They wanted it to look like the boneless part of a backrib."
That's why Mandigo is adamant that he was not the father of the McRib, despite getting the credit for it all these years. [More]

Still others use the McRib to bash modern hog production methods.

Bad news for fans of the infamous McRib: The Humane Society filed a legal complaint against Virginia-based Smithfield Foods, which supplies the pork for McDonald's sandwich. In an undercover operation from 2010, the animal rights group says it uncovered a number of disturbing farming practices, including the use of tightly confining gestation crates that cause sows to suffer "from open pressure sores and other ulcers and wounds," with nary a veterinarian in sight. Will these gross allegations sully the reputation of the barbecue-sauce-slathered sandwich?[More]

But the most curious element is the intermittent appearance of the McRib on the MacDonald's menu. There is even a theory for that.

Now, take a look at this sloppy chart I’ve taken the liberty of making. The blue line is the price of hogs in America over the last decade, and the black lines represent approximate times when McDonald’s has reintroduced the McRib, nationwide or taken it on an almost-nationwide “Farewell Tour” (McD’s has been promising to get rid of the product for years now).

Key: 1. November 2005 Farewell Tour; 2. November 2006 Farewell Tour II; 3. Late October 2007 Farewell Tour III; 4. October 2008 Reintroduction; 5. November 2010 Reintroduction.
The chart does not include pork prices leading into the current reintroduction of the McRib, but it does show it on a steep downward trend from August to September. Prices for October, 2011 hogs have not been posted yet, but I suspect they will go lower than September—pork prices tend to peak in August, and decline through November. McDonalds, at least in recent years, has only introduced the sandwich right during this fall price decline (indeed, there is even a phenomenon called the Pork Cycle, which economists have used to explain the regular dips in the price of livestock, especially pigs. In fact, in a 1991 paper on the topic by Jean-Paul Chavas and Matthew Holt, the economists fret that “if a predictable price cycle exists, then producers responding in a countercyclical fashion could earn larger than ‘normal’ profits over time... because predictable price movements would... influence production decisions.” At the same time, they note that this behavior would eventually stabilize the price, wiping out the pork cycle in the process).
Looking further back into pork price history, we can see some interesting trends that corroborate with some McRib history. When McDonald’s first introduced the product, they kept it nationwide until 1985, citing poor sales numbers as the reason for removing it from the menu. Between 1982 and 1985 pork prices were significantly lower than prices in 1981 and 1986, when pork would reach highs of $17 per pound; during the product’s first run, pork prices were fluctuating between roughly $9 and $13 per pound—until they spiked around when McDonald’s got rid of it. Take a look at 30 years of pork prices here and see for yourself. Also note that sharp dip in 1994—McDonald’s reintroduced the sandwich that year, too. Though notably, they didn’t do so in 1998.
(I’m sure all the sharp little David Humes among us are now chomping at the bit—and you’re right to do so! This proves nothing. It is just correlation—and the sandwich doesn’t always appear when pork prices are low. In fact, the recent data could prove that McDonald’s actually drives pork prices artificially high in the summers before introducing the sandwich—look at 2009’s flat summer prices. Could that be, in part, because there was no McRib? On the other hand, food prices were flat across the board in 2009 so probably not. So, no, this correlation proves nothing, but it is noteworthy.)
Because we don’t know the buying patterns—some sources say McDonald's likely locked in their pork purchases in advance, while others say that McRib announcements can move lean hog futures up in price, which would suggest that buying continues for some time—and we can’t seem to agree on what the McRib is made of—some sources say pork shoulder, others say a slurry of offal—it’s hard to really make any real conclusions here.
The one thing we can say, knowing what we know about the scale of the business, is that McDonald’s would be wise to only introduce the sandwich (MSRP: $2.99) when the pork climate is favorable. With McDonald’s buying millions of pounds of the stuff, a 20 cent dip in the per pound price could make all the difference in the world. McDonald’s has to keep the price of the McRib somewhat constant because it is a product, not a sandwich, and McDonald’s is a supply chain, not a chain of restaurants. Unlike a normal restaurant (or even a small chain), which has flexibility with pricing and can respond to upticks in the price of commodities by passing these costs down to the consumer, McDonald’s has to offer the same exact product for roughly the same price all over the nation: their products must be both standardized and cheap. [More]

This strange sandwich provokes strange reactions in consumers. But it's most lasting effect may be the piling on consequence of yets another restaurant/grocery offering that should not be examined in detail.

For my mind, this is simply an example of a culture that values quantity over nutrition in food. And one with an abnormally high sweetness demand. McRibs are probably little worse than other fast-food offerings, and as for eating offal, that too is simply a cultural and economic affectation. Protein is protein, and if you don't like the idea of "variety meats", the McRib is simply one way to avoid knowing you're eating them.