What’s hiding in your meat? And how to protect yourself
This article was written for Prevention magazine in 2006.
Feed is a large portion of the expense of raising a food animal, so a major cost-cutter involves what the feed industry describes as “recycling” proteins, minerals, and other nutrients from a huge range of sources. Legally, these ingredients may include anything from by-products of metal manufacturing to a substance called “animal digest,” made from the carcasses of various species.
But cheap comes at a price, warns microbiologist Margaret Mellon, PhD, JD, director of the Union of Concerned Scientists’ food and environment program. “The system is out of control, with dangerous and disgusting items going into animal feed, and plenty of health implications,” she says.
You already know that the 20 million pounds of antibiotics given to food animals annually — some 70% of our total usage — contribute to drug resistance, making human medicines less effective. Prevention covered this issue in “The Superbug in Your Supermarket” (July 2009). Read on for more risks concealed in your meat. Check the sidebar below, “Where’s the (best) beef?” for buying information on safe products, and tell your Congressional representatives what you'd like to know is, or isn’t, in your meat.
Talking trash
The refuse of many industrial and agricultural operations finds its way into the feed trough, according to a 2007 paper in Environmental Health Perspectives. Its authors reviewed research and regulations on feed and discovered, for example, that it may include dead, dying, and disabled animals, as well as ones with diseases such as tuberculosis or anthrax. The 2009 ban on “downer” cattle, which cannot walk, did not change that; the prohibition applies only to the ones destined immediately for human consumption.
However, a wide range of sick or deceased creatures take a detour, then arrive at your grocery store. That happens when they’re rendered (cooked, ground, and pressed) and fed to cattle, hogs, and other food animals. Laura Alvey, spokeswoman for the FDA’s Center for Veterinary Medicine, which regulates feed, calls this “a means of salvaging valuable protein and fats.” The rendering mixture can also legally include hog and cattle manure, euthanized household pets, hair and skin, zinc oxide reclaimed from furnace emissions, restaurant and cafeteria waste, and food adulterated with rodent droppings.
Safety issues arise because some waste materials contain Salmonella, E. coli, and other pathogens, including the antibiotic-resistant ones that result when animals are fed continual low doses of antimicrobials as growth promoters, according to many studies, including a 2005 review from the Johns Hopkins Center for a Livable Future, published in Public Health Nutrition.David Wallinga, MD, director of the food and health program of the Institute for Agriculture and Trade Policy, notes that this magnifies antibiotic resistance. “As animals eat the feed that’s contaminated with resistant microbes, the pathogens mutate and swap genes in the new hosts’ guts, producing even more drug resistance and, in turn, hard-to-treat human diseases,” he says.
Waste products can also include carcinogens, such as PCBs, dioxins, heavy metals like arsenic, and substances produced by molds, says the Environmental Health Perspectives review. Some become increasingly problematic as time goes on. That’s because animals store certain toxins, such as dioxin, in their fat, according to the Public Health Nutrition paper. When living animals eat the fat of dead ones, the hazardous substances become ever more concentrated, an effect called bioaccumulation. The Institute of Medicine has recommended against this feeding practice, since it increases human dioxin exposure.
Funky chicken
If you’re health-conscious, chicken is probably your go-to meat. However, numerous studies link eating it to skin, lung, bladder, and prostate cancers, as well as to heart disease and nephritis. Scientists trace the illnesses to some 2 million pounds of arsenic given to chickens each year to speed growth (an effect of antimicrobials on animals that is not fully understood), kill parasites, and pigment the meat.
Arsenic manufacturers claim the chemical is in a safe form when the bird eats it, but recent science indicates that for humans there is no risk-free arsenic — either the specific type that bird eats or the chemical form this can morph into within the bird’s body or within the body of the human who eats the poultry. “We have no certain evidence that, for humans, any type or any amount of arsenic is harmless,” says Wallinga, who is lead author of a 2006 review of its use in the poultry industry. “The more you get, the more you increase your risk of disease.”
Arsenic does not appear to be necessary for poultry production. Organic farmers do not use it, and one of the world’s largest producers of conventional (that is, not organic) chicken, Tyson Foods Inc., claims to be doing without it.
The poison doesn’t stop with the chickens, though. Some of the arsenic chickens excrete, along with the drug-resistant bacteria created, ends up in beef, according to papers in Environmental Research and other scientific journals. That’s because poultry litter — including feces, feathers, wood chips, and dead birds — is scooped up from vast chicken operations, allowed to sit, then fed to cattle, explains Steve Roach, MA, public health program director for Food Animal Concerns Trust.
As far back as 1967, the FDA warned against this practice, saying it “was impossible to conclude that it was safe,” according to the Johns Hopkins report. These concerns have surfaced repeatedly, including in 1997, when the Physicians’ Committee for Responsible Medicine reported in Preventive Medicine that poultry litter passed on toxins and pathogens.
However, its use continues, and the North Carolina Cooperative Extension Service explains its logic. The mixture is an “economical and safe source of protein, minerals, and energy” that becomes edible in as little as three weeks after sitting in so-called deep stacks, says the service. Further, selling the litter gives the poultry operation an income stream and may save a beef producer $20–$50 per animal.
How now, mad cow
Cattle brains and spinal cords are not allowed in any animal feed, according to Alvey. That’s because these central nervous system parts are where most (but not all) of the abnormal proteins, or prions, that cause bovine spongiform encephalopathy are found. Also called BSE or mad cow disease, the deadly sickness infects cows that eat the infected meat. The illness devastated the British cattle industry in the 1980s and 90s and was found in the US in 2003.
Humans who eat prion-contaminated beef can develop a related fatal neurological disease. Because prions are heat-resistant, cooking does not destroy them. Despite the concerns, a loophole allows the abnormal proteins to sneak into cattle feed, says the Environmental Health Perspectives paper. That happens when feed containing other parts of the CNS is given to poultry, and then bovines eat the poultry litter — creating a hazardous cycle. Alvey says the FDA has studied this risk and terms it very low.
Another potential problem, say food-safety advocates, is the difficulty of excising the central nervous system parts. In a DHHS publication, cattle industry representatives report that it’s tough to ensure complete removal. You’d have to butcher very carefully, explains Roach, and doing so in a fast-paced slaughterhouse is difficult. “Infected material may also splatter, and it takes very little to spread the disease,” he says.
Against the grain
Cattle naturally eat grass. However, many consume grain, which makes them grow quickly and marbles their meat with fat. Because the unnatural diet is overly acidic, it causes them to develop liver abscesses that require antibiotics. Cattle get even more antibiotics to make them grow faster, as well as when they are fed an ethanol industry by-product called distillers grain, according to Roach. (Ethanol production uses yeast to ferment the grains, and the drugs, including penicillin and virginiamycin, keep bacteria from fouling the process, he explains.)
Remarkably, though cattle appear to get plenty of antibiotics — purposely to prevent liver abscesses and to speed growth, as well as inadvertently via distillers grains — their meat can become infected with E. coli O157, which is sometimes fatal in humans, according to the CDC. In 2007 and 2008, O157 contamination led to major meat recalls: more than 2 million pounds of ground beef each year, along with millions of pounds of related products such as meat pizza, according to the USDA Food Safety Information Service. “Distillers grain appears to stress bovine digestive systems, causing this bacterium to overgrow — despite the antibiotics,” explains Roach.
Poisoned pet food
In 2007, Americans were shocked when melamine-tainted pet food sickened and killed cats and dogs nationwide. When that pet food was discarded, however, it ended up (legally) in animal feed, according to the Food Safety Information Service. After testing the melamine-laced chow and the hogs and chicken that had been exposed to it in six states, the agency decided that the poison, which causes kidney failure, had likely been diluted enough to make the animals safe for humans to eat. The pigs and poultry were slaughtered and their meat sold to the public.
After further investigation, indictments were brought against officials from U.S. and Chinese companies allegedly responsible for the melamine. No prohibitions were issued against future use of discarded pet food in animal.
“Our food regulators don’t say, ‘here’s a risk, let’s eliminate it,’ like they do in some countries,” says Wallinga. “Instead U.S. officials figure out a politically acceptable level of risk in each case. It makes it difficult for consumers to know what’s safe.”
WHERE’S THE (BEST) BEEF
“A lean piece of organic, grass-fed meat is good for you,” says David Wallinga, MD, director of the food and health program of the Institute for Agriculture and Trade Policy. Look for packages with the green-and-white “USDA Organic” label, he says, and preferably a USDA grass-fed designation as well. To find products in your area, log onto eatwellguide.org or your state’s agriculture-department website for the whole-foods supermarkets, grocery stores, restaurants, farmers’ markets, and local farms that carry them.
If buying safe meat strains your budget, reduce the amount you consume in favor of more fruits, vegetables, whole grains, low-fat dairy products, and plant protein sources such as legumes — a food plan often called flexatarian. Wallinga calls this a healthy choice, as does a 2005 review article in Public Health Nutrition.
If you worry that cutting back on meat means you won’t get enough of its complete proteins, with their full range of essential amino acids — don’t. The PHN paper cites UN Food and Agriculture Organization research showing that if you have a diverse diet, you’ll get varied plant proteins, which end up complementing each other, providing the amino acids you need.
c. Stephanie Woodard.
c. Stephanie Woodard.
