When “pink slime” became the media persona non grata a few months back, the food item foodies love to hate launched a cavalcade of slime-related news. Next came white slime, then tuna scrape – all variations on the theme of pulverized scraps. Flesh not fit for fillets, which is turned into a ground (slime, goop) product.

In each of the three scenarios – pink slime (beef), white slime (pork, chicken, lamb, turkey), tuna scrape (tuna) – the product is derived from bits and pieces that are left behind after the prime pieces have been removed.

If sustainable food advocates promote eating nose-to-tail (eating as much of an animal as possible), then are these products being maligned the greenest way to go? These processes minimize waste and use as much meat as possible from the animal. If raising animals for meat is so environmentally intensive and we are determined to eat meat, do we really have the luxury of being so particular about which parts of the animals we eat?

Here’s the skinny:

White slime: Mechanically separated pork, chicken or turkey

As the USDA describes it, mechanically separated meat “is a paste-like and batter-like product produced by forcing bones, with attached edible tissue, through a sieve or similar device under high pressure to separate bone from the edible tissue.” The remaining fragments (the USDA limits how many bits of bone are acceptable) are ground up into a paste and added to other processed meats.

By law it must be labeled as "mechanically separated" pork, chicken, lamb or turkey. Mechanically separated beef was prohibited for use as human food in 2004 due to concerns that spinal tissue (potentially carrying mad cow disease) could get mixed into the meat. Mechanically separated poultry and pork are still allowed.

See the magic here:

Gross or green? Oh, this is really quite gross — yet it uses a lot of trimmings that would otherwise be wasted. White slime may be the most aesthetically offensive of the three, but there doesn’t seem to be much of a bona fide health danger.

Tuna scrape: 'Nakaochi scrape' or tuna backmeat

In all fairness, tuna scrape isn’t really slime or goop at all. The Food and Drug Administration (FDA) defines tuna scrape as "tuna backmeat, which is specifically scraped off from the bones, and looks like a ground product." Basically, it’s ground tuna, and it's most commonly found in sushi rolls.

And again, waste not, want not? Well, yes, if it’s safe. But last week a salmonella outbreak sickened 116 people. The Centers for Disease Control and Prevention (CDC) issued a warning, and the scrape was scrapped. The tuna scrape had been traced to nearly 71 percent of sushi orders in the outbreak and 53 percent of "spicy tuna orders," the CDC stated. California-based importer Moon Marine USA Corporation issued a recall of more than 50,000 pounds of the frozen yellowfin tuna product from India, an FDA spokesman told AFP, after it had been identified as a cause of the outbreak.

According to Michael Doyle, director for the Center for Food Safety at the University of Georgia, who spoke with NPR about the substance, "My rule of thumb is that raw food of animal origin should be cooked before it's eaten," he said. He also notes that, due to the fish being ground up, there are greater chances for contamination and that, while the “tuna scrape” has been frozen, it is not necessarily free of germs.

Freezing is good at killing parasites, Doyle says, but bacteria like E. coli and salmonella often rest through a freezing, emerging from their slumber just as dangerous as they were before.

Gross or green? If you’re expecting lush slivers of prime tuna in your sushi rolls, these ground bits of scrape may seem gross. Otherwise, you’re saving part of an overfished species from the waste bin, but you risk food borne illness.

Pink slime: Lean, finely textured beef

Referred to by Jon Stewart as "ammonia-soaked centrifuge separated byproduct paste," lean finely textured beef (LFTB) is a product designed to recover clingy bits from carcass trimmings, as well as an attempt to eliminate pathogens from ground beef. Using fatty beef trimmings, which are especially susceptible to E. coli and salmonella contamination, the meat company Beef Products Inc. created a product that could be sanitized to kill the bacteria.

In the process, trimmings are heated to 100 degrees F and spun inside a centrifuge to separate the meat from the fat. After the fat is removed, the remaining beef bits are treated with ammonia hydroxide to kill bacteria. They are then ground up, frozen into blocks and added to other beef products. Ever since this ammonia-treated meat was introduced around a decade ago, safety officials say they rarely find toxic E. coli in, for example, school hamburger.

People who demand "real food" have been in an utter outrage, but here’s the dilemma, as noted by nutritionist Marion Nestle (no shrinking violet when it comes to food politics): “LFTB solves an enormous problem for meat producers. Only about half the weight of the 34 million cattle slaughtered each year is considered fit for human consumption. The rest has to be burned, buried in landfills, or sold cheaply for fertilizer or pet food. LFTB recovers 10 to 12 pounds of edible lean beef from every animal and is said to save another 1.5 million animals from slaughter.”

That sounds like a compelling argument for sustainability. However, it kind of misses the point.

The problem is that LFTB is used because of the high level of bacteria found in meat, courtesy of factory farming and our methods of industrial meat production on a scale that’s far too expansive to avoid deleterious effects. E. coli is common on factory farms, and even “healthy” cattle is routinely fed so many antibiotics that E. coli, salmonella and other pathogens are developing resistance to commonly prescribed drugs. Healthier farms could alleviate our reliance on ammonia and other sanitizers to keep our food safe.

Gross or green? Pink slime may be a sustainable option in terms of waste and utilizing every part of an animal that has been raised for food. But the truly green option would be a return to smaller livestock operations that rely on more humane and organic practices.

Pink slime and other animal goop we commonly eat: Gross or green?
Pink slime is said to recover 10 to 12 pounds of edible lean beef from every animal and save another 1.5 million animals from slaughter, but does that diminish