Pink Slime | Chemical & Engineering News
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Web Date: April 16, 2012

Pink Slime

Ammonia’s the player in this beleaguered meat product
Department: Science & Technology
News Channels: Analytical SCENE, Biological SCENE, Environmental SCENE
Keywords: Pink slime, beef, food chemistry, ammonia
Chips of lean finely textured beef, also known as pink slime, in frozen form.
Credit: Beef Products
A photo of "lean finely textured beef" aka "pink slime" in frozen form: little pink tubes.
Chips of lean finely textured beef, also known as pink slime, in frozen form.
Credit: Beef Products

What a difference a few years make for South Dakota meat processor Beef Products Inc. In 2008, the Washington Post lauded the company’s process for eliminating bacteria from beef. For an industry haunted by the specter of Escherichia coli outbreaks from the 1990s, it seemed like a triumph of technology over nature. Today, though, that same process is being vilified by the media and the public. And the company’s marquee product, which it calls boneless lean beef or lean finely textured beef (LFTB), has become infamously known by the unappetizing name of “pink slime.”

The story of pink slime is a case study in what happens when companies that lack transparency clash with a public that wants to make well-informed food choices and balks at mysterious-sounding food-processing efforts.

The slime (or LFTB, depending on whom you talk to) comes from beef trimmings, says James S. Dickson, a food microbiologist at Iowa State University who has conducted studies in collaboration with Beef Products. After cutting a cow carcass into roasts and steaks, “you end up with these odd-sized pieces of meat,” which have high fat content and can be susceptible to bacterial contamination, he says. In the name of reducing waste in beef production, companies including Beef Products and agribusiness giant Cargill turned to chemistry.

At Beef Products, Dickson explains, technicians release the beef from the trimmings by heating trimmings to roughly 100 °F, which liquefies fat. They then separate the fat and protein with a spin on an industrial centrifuge. To kill bacteria, the protein portion is exposed to a puff of ammonia gas. Ammonia reacts with water in the meat to form ammonium hydroxide, raising the processed product’s pH to as high as 9.35, according to a 2001 Beef Products study obtained by the New York Times.

“Bacteria can’t tolerate extremes in pH and they simply die,” Dickson says. The resulting finely textured beef gets frozen and cut into small chips. When the finished product is blended with other trimmings to make ground beef, the level of ammonia that results is about 0.02 g for every 100 g of meat, Beef Products spokesman Rich Jochum tells C&EN by e-mail. That’s on par with other foods and is less than what’s contained in products such as salami and bleu cheese, according to the University of Michigan’s Risk Science Center, citing a 1973 analysis of foods’ ammonia content (Am. J. Clin. Nutr. 1973, 26, 487).

Beef Products founder Eldon Roth was the first to patent ammonia as a beef sanitizer, but companies have several ways of making finely textured beef—most methods use food-grade acids such as citric or lactic acids as antimicrobials.

This isn’t even Beef Products’ first time through the media meat grinder. A 2009 New York Times investigation revealed that its ammonia treatment didn’t always finish off bacteria. “While the pH enhancement process is very effective in eliminating pathogens, no process is foolproof,” Jochum wrote. The method “is only one step in a multihurdle food-safety system,” including a sample testing program used to improve the process and ensure contaminated products don’t reach consumers, he adds.

“We’re not in the habit of endorsing products or companies, but we’ve seen no reason to believe that the ammonia process itself is dangerous for consumers,” says Sarah Klein, a food-safety attorney for the nutritional watchdog Center for Science in the Public Interest.

“That’s not to say that American consumers want it,” Klein adds. Safety is one of many factors that can determine food choice, she explains. “The consuming public may say, ‘We don’t care if it’s safe, we don’t want it anyway.’” Plenty of other products represent the high-tech marriage of engineering and food, she says. “Pink slime is just the most well-known this month.”

In the aftermath of pink slime ire, Department of Agriculture officials on April 4 said they’ll grant requests from some meat producers to list lean finely textured beef as an ingredient on packaging. Federal officials had previously agreed with Beef Products that ammonia was a processing agent and didn’t need to be listed on labels, according to the 2009 New York Times story. It was a former scientist from USDA, Gerald Zirnstein, who coined the term “pink slime” in disgust over that decision.

“Food isn’t just about nutrition, just like politics isn’t just about policy,” says Robin D. Hanson, a professor who teaches health economics at George Mason University. “There’s just an ick factor about the kinds of things that go into our foods.”

Though it may be too late to mend pink slime’s image, Klein adds, “the industry could do a better job of educating consumers about the benefits of not wasting parts of an animal, to avoid the public outcry that happens when people feel they’ve been misled.”

Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society
Tomc (April 16, 2012 12:54 PM)
What we have all been exposed to with this "pink slime" coverage is a classic example of media sensationalism aimed at ratings and not based on facts. Now some clear facts here. The only differences between the trimmings used to make ground beef, as we the consumer recognizes it, and the trimmings used to make LFTB is the lean beef to fat ratio. LFTB starts by using higher fat trimmings. To achieve the higher lean ground beef that we all desire economically, the lean is separated from the fat and the lean is added back into the ground beef. The process of separating lean from fat is accomplished with centrifugal force similar to separating cream from milk. LFTB is nutritionally equal to ground beef or even improved due to higher lean content. On to the subject of ammonia hydroxide. The association of ammonia used as a cleaning or sanitizing agent is very misleading. After the lean beef is separated from the high fat trimmings. Food grade ammonia gas, which is naturally occurring in many foods including beef, is used to slightly elevate the ph of the product. Elevating the ph of the beef creates an environment that is unfriendly to bacteria. So the intent here is truly food safety. Next, I have seen a lot of back and forth about labeling. This is a tough one. There are a couple questions that have been posted many times. Do you label it ground beef with lean beef added? Or, do you put on the label ammonia used to elevate the level of already existing ammonia? Contrary to what we have been led to believe, this debate has been going on throughout for quite some time. What we should really be asking ourselves is, who's going to suffer? Well, simple economics will tell us, as consumers, we will all pay more for beef at the meat counters due to the lose of quality lean beef in the market place. I would encourage that we all do some research for ourselves and not buy into the hype. A well informed consumer now has the tools to, and will, make good choices.
Carmen (April 18, 2012 11:50 AM)
Thanks for your comment Tomc. I didn't have room to mention it in my article, but one incident that clearly contributed to the pink slime saga was a celebrity chef who back on 2010 brought attention to the stuff by pouring sanitizing/cleaning ammonia over beef in a TV broadcast. It is an incorrect image but it is one that sticks. What's most important to me is the consistency of the ammonia process-- ie, verifying that all the harmful bacteria are killed off.
CisT (April 23, 2012 9:13 AM)
According to a comment to me on an article in the DMR newspaper from a BPI representative there are about 40 mg of ammonia left in the beef per 3 oz hamburger. This varies from your amount quite a bit. I wonder what the real amount is and who did the testing. I think that is enough to call it an additive and I think the food should be labeled. Nitrates occur naturally but they are not all that great to eat or drink and are on labels. When people pay for ground beef they are not thinking "trimmings treated with ammonia." It is a matter of honesty. Do a search for research on this process. You will not find much study about if there have been any by products formed, just that bacteria were killed. This company contributed heavily to some politicians and maybe that money would have been better spent on studies of the long term health effects of the product. Also, this ammonia treatment is used for more than just meat. It is also used to treat fruit. How much will the average person take in per day due to added ammonia? To say that the bottom line is higher prices is fine but misses the point. Wages have barely grown for decades and the wage gasp between rich and poor is at a high level here in the US. We should not substitute low quality food for a living wage. We are saying "let them eat dogfood".
CisT (April 23, 2012 9:51 AM)
Oops. my mistake on the previous comment. With one sig fig there is not that much variation in the ammonia left in the meat. But is this amount ok for all consumers? Stomach acid decreases with age. Is eating too much of this a concern for the elderly?
wintj (April 24, 2012 4:04 PM)
I must observe that anyone who has ever eaten a sausage should consider the issue of "pink slime" to be innocuous-further, it does not look like pink slime to me, rather more like ground beef, which itself is rather gruesome. Perhaps the organized attack should have been focused on ground beef, if "icky" were the defining feature. After all, the innate properties of ground beef, with higher fat content and higher bacterial content than LTB, are poorer than those of LTB. It looks like the shoe has been placed on the wrong foot. Interesting what one clever person, designing to discredit a foodstuff, can accomplish by capturing the imagination of others. And by suggesting that 200 ppm of a very natural substance and flavorant, ammonia, were a health risk?
Cis T (April 27, 2012 11:56 PM)
There are plenty of natural substances that I would not want to eat or be exposed to at a 200 ppm level.
etisdale (April 24, 2012 12:41 PM)
While "pink slime" might be a triumph for Beef Products Inc. and for industrial food processing chemistry in general, it is, in itself, a sad commentary on the state of our food production system. Sad because we have to go to such lengths to ensure the safety of our food, and sad because it shows how far removed food production is from the hands of the general population.
Andreas Grueneberg (April 24, 2012 12:44 PM)
What this is all about is that we as a society have lost touch with our food. We have beenmarketed into believing that cheaper is better, and that convenience is more important so that we can all go out and spend more time shopping for stuff we don't need with our families, instead of doing one of the most basics things known as cooking and eating with our families. "Food and culture are intimately linked. If we do not care where our food comes from, neither do we care about our culture"
Other than the color of pink slime, this whole thing reminds me of the 70's movie staring Charlton Heston "Soylent Green".
wintj (April 25, 2012 10:42 AM)
Irony does not work with this crew. Regardless of assertions to the contrary, the food supply is now safer than it has ever been, based on the qualities of bacterial contamination and other adulteration. It is also less expensive. Adulteration was immeasurably worse in the "good old days," depending on the reporting period. Focusing on average considerations, ground beef containing "pink slime" is healthier than ground beef without. And such food is hardly less appetizing, based on the inherent properties of ground beef. Have you been to a slaughter hous or closely looked at the material? LTB provides lower fat content and is bacteriologically cleaner. Animal meat is inherently contaminated, regardless of the skill in producing it. The sad comment on this theatrical episode discrediting "pink slime" is that more injury, such as hemorrhagic colitis, will result because of its exclusion. And in general, it is simply immoral to waste any useable part of an animal sacrificed for our food. And it is doubly immoral to sacrifice more animals to make up for a portion fashionably deemed "unappetizing."
Matt (August 27, 2012 8:20 PM)
BLBT has been used for over 20 years and is made from 100% beef, no other ingredients. The raw material processed is edible product inspected by USDA. BPI's finished product is also inspected by USDA. If you are claiming that USDA is worthless then you really need to be looking at everything in your kitchen or restaurant on the same terms. There's a lot to the "story" than you can imagine but the product that BPI sells is FAR BEYOND the norm as far as what the company voluntarily subjects their product to with regards to the level of sampling and testing of their product. If you are disputing the fact that ammonia is used as a processing are again misled as ammonia is used in a multitude of foods you consume every day not limited to cheese, pudding, and chocolate. I ask that you do not believe everything you read, see, or hear with regards to the food you eat everyday. Just a thought...

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