Although this isn’t really the season for an E. coli O157:H7 infection – such infections are most common in the summer and spring – a recent New York Times article (requires free registration) about the lengths to which slaughterhouses are going to eliminate such infections got me to thinking.
There are a couple of reasons we’ve had this plague visited upon us: we mistreat our beef cattle and we mistreat ourselves. There isn’t a whole lot we can do to deal with the mistreatment of cattle on a feedlot, but there is a lot we can do to keep from mistreating ourselves. Before we get into the steps we can take to protect ourselves from E. coli O157, let’s take a deeper look at where this bug comes from and what it does.
There are countless millions of harmless E. Coli bacteria in the digestive systems of cattle just as there are in our own. But when cows are fed on grain, which contains many more calories per pound than does grass or hay, they gain weight and fatten more quickly, and the conditions in their GI tracts changes to favor E. coli O157. If the cattle are ill or stressed – conditions common to a feedlot – they become even more susceptible. The first E. coli O157 infection was reported in 1982, which makes it likely that the bug mutated from a non-pathogenic E. coli around that time.
Feedlot operators basically pack cattle together in close quarters in which they stand or lie in manure all day, feed them an unnatural diet that changes the environment within their digestive systems, make them sick, treat them with antibiotics to fight the infections such conditions cause, add growth hormones to increase weight gain a little more, and ultimately slaughter them. Most of the beef you buy has suffered this fate. Even the beef that ends up labeled ‘Organic’ pretty much goes through the same process except it gets fed ‘organic’ grain and doesn’t get the antibiotics or the hormones, which is an improvement for you but not much of one for the cow. The meat from these cattle can still be contaminated since the majority of the E. coli arises as a function of grain feeding.
As these infected animals defecate they add more E. coli O157 to all the manure in which they live the last few weeks of their lives. If you’ve ever seen a feedlot you’ll know what I’m talking about when I tell you that these cattle are covered in manure. It’s all over their legs, bellies and usually pretty much everywhere. And this manure coating is swarming with E. coli of all kinds including the deadly O157:H7 variety. When the cattle are killed and processed some of this bad E. coli from their hides makes its way into the meat because it’s virtually impossible to get rid of all of it.
It doesn’t really matter if there is a little bad E. coli on the steaks we buy because the bugs are on the outside of the steak and the cooking process kills them. The problem arises mainly from hamburger because your pound of hamburger meat can come from several different animals (your steak, obviously, comes from only one), and the E. coli can – and often is – deep inside the ground beef. If you (or McDonald’s) doesn’t cook the hamburger enough to really get the inside cooked, you could get a nasty dose of E. coli O157:H7.
Here is an excerpt from the Times article on the steps taken to rid the meat of E. coli, which shows where hamburger comes from:
Once the animal is killed, the hide is removed, first by knives and then by machines, in a manner intended to keep it away from the exposed carcass, starting near the anus and hind legs.
After each cut is made to remove the hide, a worker follows behind with a steam vacuum to kill and suck away microbes. The carcass, pulled along on an overhead rail, is then sent into a cabinet with pivoting nozzles that soak it with water at about 185 degrees.
After the head is removed and before the animal is gutted, the carcass is sprayed with a mild acid wash, again to reduce the level of microbes. Besides removing the hide, one of the most critical steps to prevent E. coli 0157:H7 comes when the animal is eviscerated and its internal organs are removed.
The workers who remove the organs are careful not to cut the bowel, which could spread manure, and a worker looks over the internal organs to make sure the intestines are intact. The carcasses are then sawed in half, and the cut line is steam vacuumed.
In one of the most important interventions, the split carcasses are sent into a 30-foot-long, hissing stainless-steel cabinet, where rows of nozzles spray them with steam for at least 13 seconds before they enter a second chamber that douses them with a disinfectant for at least 15 seconds.
The last step comes after the carcasses have been cut into steaks and roasts and leftover scraps, with the latter tossed into 2,000-pound bins for grinding into hamburger meat. Workers are assigned to cut at least 60 four-inch by one-half-inch strips from each lot of trimmings; a lot is five 2,000-pound bins.
Those samples are then ferried to a laboratory, where they are mixed with solution that encourages E. coli 0157:H7 to grow. After incubating for eight hours, the samples are tested, and if positive for the germ, that lot is diverted from being used as ground beef. Instead, it is used in cooked products or otherwise processed to kill the microbes.
All this and a few bugs still make it through.
Why don’t cows get sick from E. coli O157? Because the bacterium isn’t able to bind to the walls of the GI tracts of cattle. In humans, however, it’s a different story. The E. coli O157 can and does bind to the cells that line the human intestinal tract leading to all the problems it causes.
In humans E. coli O157 infections usually involve bloody diarrhea and sometimes kidney involvement. Although the diarrhea is severe, most people recover from it without long lasting problems. But about 8 percent of those with the infection can develop a form of kidney failure that can be fatal. Most recover from the kidney failure but many continue to have such problems as blindness, paralysis, and intermittent or even persistent kidney failure over the long term. It is not a disease to be trifled with.
Despite the fact that people aren’t eating all that much more beef now as compared to before and despite the fact that the beef industry is now shelling out $350 million per year to keep the bug out of the meat supply, the number of E. coli O157 infections are on the rise. Why? A couple of reasons, I think.
First, like any bacteria, E. coli O157 tends to reproduce and spread. I would imagine that it would be found in many more feedlots now than it would have been 10 years ago. And more people are eating their beef as fast food these days, which means that more is consumed as hamburger. Finally – and I’ll admit that this is speculative on my part – more and more people are obese, insulin-resistant and suffer from heartburn and gastroesophageal reflux disorder (GERD). What does this have to do with it? Plenty, in my opinion.
Prilosec, Nexium and all the other proton pump inhibiting drugs are some of the most widely prescribed drugs in this country. People can now by Tagamet, Pepsid and other H2 inhibitors over the counter. And people gobble Tums, Rolaids and other antacids by the ton. What do all the drugs have in common? They all treat GERD, and they all do so either by neutralizing stomach acid or by preventing its production. In either case the acidity of the stomach decreases, which means that the symptoms causes by this stomach acid getting on the wrong tissues (the esophagus and throat) are lessened or eliminated. But at what cost?
As my grandmother would have said, God put that strong acid in your stomach for a reason. And indeed He did. When food travels through the esophagus and dumps into the stomach it goes into a strong acid bath. This acid breaks down the large proteins into much smaller peptide chains and even individual amino acids, which is the first real phase of digestion. When this acid mixture then makes its way into the first portion of the small intestine, the acid stimulates the production and release of strong alkaline digestive juices that neutralize the acid and activate many of the enzymes that operate in an alkaline environment. If you reduce the amount of acid in the stomach with drugs or antacids in an effort to reduce the symptoms of GERD, you end up impairing the very first step in the digestive process. Reduced acid in the stomach means compromised protein digestion and it means reduced production of the alkaline digestive juices. Reduced alkaline digestive juices mean the enzymes don’t work as well. Getting rid of or decreasing stomach acid – which the TV ads all tell us is a good thing – markedly hobbles the entire digestive process. It’s hardly any wonder that those who suffer from GERD and take these meds usually pay with problems throughout their GI tracts.
Bad as it is, the above scenario has nothing to do with E. coli O157 infections. Those come as another function of reduced stomach acid. The strong acid in the stomach is on the front lines of our immune defense system. If we eat bacteria and/or viruses (which we do all the time) or breathe in bacteria and/or viruses that get stuck in the mucus of our respiratory tree and are moved to the throat and swallowed (which we do all the time), the strong acid in the stomach kills these bacteria before they can invade and cause us problems. If we’ve reduced the strength of this stomach acid, we’re leaving ourselves open to infections we wouldn’t otherwise get.
A few studies have looked at anti-GERD drugs and pneumonia infections, and it turns out that those taking these medications are indeed more prone to pneumonia. I would suspect they would be more prone to E. coli O157 infections as well. The stomachs of cattle are less acidic than the stomachs of humans, so it stands to reason that human stomach acid would go a long way toward killing E. coli O157 before they get to the bowel where they cause the problems.
I have only anecdotal information on this front, but I think it is more than a little suggestive. Whenever people travel from the US to Mexico they tend to eat food contaminated by a type of E. coli that is different than the strain that normally inhabits their GI tracts. This strange E. coli then causes what we all know as the Turistas or traveler’s diarrhea. It has been my experience on many trips to Mexico with numerous people that those who have GERD and take acid reducing drugs are always the ones who get diarrhea and/or get it the worst.
I would be interested in any experiences readers may have on the subject of acid reduction and traveler’s diarrhea. Please comment if you have experience.
Now, getting back to the cattle, we can get rid of the E. coli O157:H7. How? By switching back to grass or hay as our feed for cattle. A number of studies have shown that switching cattle from grains to roughage (grass or hay) drastically reduces the amount of E. coli O157:H7 in their manure. One study (click here for full text) performed by USDA researchers in 2003 showed that
generic E. coli populations declined 1000-fold within 5 d[ays], and the ability of the fecal generic E. coli population to survive an acid shock similar to the human gastric-stomach decreased.
The take home messages are several: always cook your hamburger meat through and through; eat mainly grass fed beef; and maintain a normal stomach acid.