Euphemistically referred to as the “trimmings,” the leftover waste products from beef processing include fat, sinew, bloody effluvia, and bits of meat. Rather than throwing this material away or selling it to a pet food company, some enterprising meat plants transform their trimmings into a product they call “lean finely textured beef” (LFTB). In case you’re wondering how a grim mixture of slop gets turned into the elegant pink snake pictured at left a delicious hamburger, here’s how: The trimmings are liquified, then put into a spinning centrifuge to separate the remaining fat globs and solid bits. The resulting liquid is then treated with ammonia gas to destroy pathogens–of which there tend to be a lot–by raising the pH, and then frozen into small squares. The frozen squares are shipped off to supermarkets and producers, where they get added to actual ground beef as filler. The final meat product is sold raw as “lean ground beef” and sold as hamburger at restaurants and in school cafeterias. [Note: BPI, the primary producer of LFTB in the U.S., claims that the photo we originally provided in the story is, in fact, an image of mechanically separated chicken, not beef a hoax. In an email to Popular Science, BPI’s Jeremy Jacobsen also claimed that “the language used to describe how it’s made and what it’s made from are 100% completely false,” but did not provide any further details. The company has also been disseminating its own photo of LFTB, and has created multiple websites aimed at improving the product’s image. Oh, and they are suing everyone who calls it “pink slime”–including Gerald Zirnstein, a USDA microbiologist who coined the term in an email to colleagues after touring a processing plant. (Zirnstein was looking into allegations concerning bacterial contamination at the time; he also wrote in his email, “I do not consider the stuff to be ground beef, and I consider allowing it in ground beef to be a form of fraudulent labeling.”)]
Each year, the FDA tests meat samples from hundreds of supermarkets around the U.S. Between 2002-2011, inspectors found that an average of 2/3 of ground beef samples contained E. Coli, the bacterium that lives in your lower intestines and helps turn your part-way digested food from a liquidy green slurry into real, bonafide poop. So how does so much E. Coli wind up in meat? PETA’s website has this vivid explanation: “When animals’ intestines are torn open during slaughter, feces spill out onto their flesh.” Then, as you know, the stuff is ground up and mixed together. Some strains of E. Coli are harmless to humans, but others can cause serious food poisoning if ingested. One notable outbreak in 1993 sickened over 400 people in three states and took the lives of three children. The culprit was a batch of contaminated burgers from the fast-food chain Jack in the Box.
Believe it or not, there’s a darker side to the aforementioned poop-in-your-burger problem: Livestock are treated with heavy courses of antibiotics and, as a result, their bodies become breeding grounds for drug-resistant bacteria. In 2011, FDA tests found that over 15% of the E. Coli in ground beef is resistant to at least one class of antibiotics. Ground beef also contains drug-resistant [Salmonella, Enterococcus, and Staphylococcus aureus. But here’s where it gets a little scary: some of the bacteria showing up in supermarket meat is resistant to multiple drugs. A 2011 study found that, of the 37% of total ground meat samples containing S. aureus, a third were found to have resistance to three or more separate antibiotic drugs. In other words, roughly 13% of meat contains harmful bacteria against which humans have no remaining defenses. (Full disclosure: We’re talking ground beef here, but poultry is worse.)
Drugs, Chemicals, Pesticides
A 2010 USDA report found that residues of hazardous chemicals, including “veterinary drugs, pesticides, and heavy metals,” were widespread in the country’s beef supply. Unlike bacteria, whose harmful effects can be avoided by cooking meat thoroughly, chemical residues stick around in meat until the meat gets broken down in someone’s stomach. Some of those toxins, including certain pesticides and heavy metals, cannot be processed by the kidneys and liver, and will therefore stick around in the body’s tissues for life.
The Thousand-Animal Burger
Maybe there’s nothing inherently gross about the fact that, when you bite into a hamburger, you could be chewing the flesh of over 1,000 individual animals simultaneously. But if you’re the chief of the food-borne and diarrheal diseases branch at the CDC, you look at that hamburger and also see the pooled bacteria from a thousand farm animals, and you know that, the next time an outbreak of drug-resistant Salmonella pops up somewhere, you’ve got your detective work cut out for you. Grinding your own beef, or having it ground by a trustworthy butcher before your eyes, ensures that no more than a few cows (the juicy chuck of one, the sirloin of another, maybe) contribute to your burger.