By Lisa Egan
Escherichia coli (E. coli) tends to pop up in the news periodically, with several multi-state outbreaks occurring each year.
But where does the bacterium come from, and how can infection be avoided?
E. coli has an interesting history. It’s been around, well, probably forever – but the bacteria was first discovered in 1885 by German pediatrician Theodore Escherich. It is a normal resident of the intestines of humans and animals, and usually does no harm. In fact, Escherichia coli can be helpful – it keeps disease-causing bacteria from taking over.
It wasn’t until many decades after its initial discovery that scientists learned that some forms of E. coli are capable of causing serious disease and death.
The strain O157:H7 is the one you hear about in the news because it is the usual culprit in food-borne E. coli outbreaks. It is the third most deadly bacterial toxin, coming in behind the pathogens that cause tetanus and botulism. An epidemic spread by undercooked hamburgers from McDonald’s restaurants in Oregon and Michigan in 1982 led to the discovery of this strain.
So, why are we seeing more frequent – and more widespread – cases of E. coli O157:H7in recent years?
In experiments on mice, Tufts University researcher David Acheson may have found the answer. When Acheson gave the animals low levels of antibiotics, the phage virus wildly replicated itself, and its magnified forces were more likely to infect other bacteria. Antibiotics also spurred the phage to pour out clouds of Shiga toxin. Acheson speculates that when farmers began the practice of feeding cattle small doses of antibiotics to spur growth, beginning in the 1950s — perhaps not coincidentally, when the first reports of sporadic HUS in children came out — they may have unleashed O157. More backing for this theory comes from epidemiological evidence. E. coli O157:H7 is a disease of affluent, developed nations — which also happen to be the ones that feed growth-promoting antibiotics to livestock.
The main source of E.coli infections in humans is cattle.
In the article The Truth About Grass-fed Beef, John Robbins explains why the bacteria is becoming such a common scourge in cattle:
It is the commercial meat industry’s practice of keeping cattle in feedlots and feeding them grain that is responsible for the heightened prevalence of deadly E. coli 0157:H7 bacteria. When cattle are grain-fed, their intestinal tracts become far more acidic, which favors the growth of pathogenic E. coli bacteria that can kill people who eat undercooked hamburger.
It’s not widely known, but E. coli 0157:H7 has only recently appeared on the scene. It was first identified in the 1980s, but now this pathogen can be found in the intestines of almost all feedlot cattle in the U.S. Even less widely recognized is that the practice of feeding corn and other grains to cattle has created the perfect conditions for forms of E. Coli and other microbes to come into being that can, and do, kill us.
Prior to the advent of feedlots, the microbes that resided in the intestines of cows were adapted to a neutral-pH environment. As a result, if they got into meat, it didn’t usually cause much of a problem because the microbes perished in the acidic environment of the human stomach. But the digestive tract of the modern feedlot animal has changed. It is now nearly as acidic as our own. In this new, man-made environment, strains of E. coli and other pathogens have developed that can survive our stomach acids, and go on to kill us.
Can those of us who enjoy consuming beef avoid contracting E. coli somehow?
Since grain-fed cattle seem to be far more prone to harboring the bacteria, would eating grass-fed beef be safer?
It’s possible, according to a study that was conducted in 1998:
A study by Cornell University has determined that grass-fed animals have far fewer E. coli (approx. 300 times less) than their grain fed counterparts. Also in the same study, the amount of E. coli they do have is much less likely to survive our first line defense against infection, stomach acid.
Since the Cornell study in 1998 many groups have tried to contest the results. A study by the USDA Meat and Animal Research Center in Lincoln Nebraska(2000) has confirmed the Cornell research.
The scientists from Cornell and the U.S. Department of Agriculture went further to observe that changing the diet from grain to hay…the natural, dried grass diet of cattle…for only five days before slaughter could reduce the number of E. coli bacteria by 80%. (source)
Even though there haven’t been any reports of E.coli that were linked to grass-fed beef, that doesn’t mean it can’t happen. The bacteria can be transmitted in the slaughterhouse. And, there is no way to know exactly how many cases of E.coli occur, period: some cases go unreported, especially if they aren’t linked to a significant outbreak.
Mark Bittman of The New York Times asked attorney Bill Marler, who has handled food-borne illness cases since 1993, about how to avoid E.coli infection. Here’s what Marler told him:
“Eat simply, locally, things that you wash well, cook well and process yourself. Wash your hands and keep your kitchen clean — especially the dish rag. Keep cold things cold and hot things hot. Keep meat and unwashed vegetables away from ready to eat food. Have a glass of good red wine.
“Think about eating mass-produced raw meat and produce like you are swimming in a pool with a thousand people you don’t know. Think of eating as described above as sitting in a bath with your significant other — hopefully less risky and much more fun.”
Cattle that are raised at pasture tend to be cleaner than those raised on factory farms, which could translate to less risk of infection at the slaughterhouse:
E. coli contamination takes place in the slaughterhouse when manure from an animal comes in contact with meat. The less manure on an animal when it enters the slaughter house, the less likely the meat will become contaminated.
It is difficult to remove all the fecal contamination from feedlot cattle because they stand all day long in dirt and manure. In a recent article in the magazine Meat Marketing and Technology, the associate editor stated that pasture-raised animals were much easier to clean “because they come from small herds raised in relatively clean pastures.” Most U.S. cattle, he said, “are raised in far larger numbers in congested and typically less sanitary feed lots.” (“The Future of Food Safety,” by Joshua Lipsky. Meat Marketing and Technology, April 2001.) (source)
Buying grass-fed beef may protect you from infection, but the only proven way to kill E. coli O157:H7 is cooking ground beef to a temperature of 160 degrees Fahrenheit. Purchasing meat from local, sustainable, or organic farms may also lower your risk. Ask your local farmer what they feed their cattle – if they are grain-fed, what kind of grain, and are they using corn (that’s the big one to avoid)? Remember, the words “natural” and “organic” can be slapped on labels now without meaning much – those animals might have been fed corn, or other grains.
Ground beef poses additional risks:
Meat producers and grocers have been banned from selling meat tainted with E. coli since 1994, but there is no federal requirement that they test it; and in three years, there have been 16 outbreaks of E. coli in ground beef. Besides the lack of self-regulation, another complication is that a serving of hamburger meat is often a mixture of different cuts from different slaughterhouses, and–even if the meat is tested–it is difficult to pinpoint the origin of the tainted portion. (source)
As a bonus, grass-fed beef provides more health benefits than grain-fed beef:
A study by researchers at California State University in Chico examined three decades of research and found that beef from pasture-raised cows fits more closely into goals for a diet lower in saturated fat and higher in “good fats” and other beneficial nutrients.
Grass-fed beef is lower in calories, contains more healthy omega-3 fats, more vitamins A and E, higher levels of antioxidants, and up to seven times the beta-carotene.
There’s another difference between cattle that are grass-fed, pasture-raised, and cattle that are grain-fed, factory raised: living conditions. Most calves start off roaming free at pasture, but after 6-12 months, the conventionally raised cows are moved to feedlots. Cattle raised on feedlots are fattened up with those grain-based diets and hormones, and are given antibiotics to prevent the infections that are rampant in the crowded, unsanitary lots. A few months later, they are hauled off for slaughter.
Grass-fed, pasture raised cows get to continue roaming and are allowed to consume the diet nature intended for them. They get to act like, well, cows.