A Quick Look At E. coli

E. coli stands for Escherichia coli, a bacteria named after its discoverer, Theodore Escherich. It is a commensal organism of warm-blooded animals - it lives in the digestive systems of mammals.

Yes, this means E. coli is a normal inhabitant of humans!

I've tested myself for E. coli, and found it - and if I were to test you for E. coli, there's a good chance it'll be there, too!

Well, let's put it this way - humans belong to one species (Homo sapiens). And yet, humans are not all the same. Some of us are more laid-back, some of us love roller coasters, some of us love stinky goat cheese, and some of us are just plain dangerous.

This is how it is for E. coli as well. Some types, or strains, of E. coli can live in humans without harming them at all - others can be very dangerous, like E. coli O157: H7. Obviously, the ones that live in our bodies without causing disease are harmless - to us, anyway.

So, a small number of E. coli strains have to potential to make people sick, but the majority of them are harmless.

Scientists use both disease-causing (pathogenic) and non-disease causing (non-pathogenic) strains in their research.

E. coli O157: H7 is a type (a strain) of E. coli - it's kind of like saying that a bank robber is a type of human being. It causes a particularly serious illness.

Pathogenic E. coli usually cause diarrhea, which is bad enough.

But E. coli O157: H7 is different from other E. coli as it causes bloody diarrhea, and may also destroy red blood cells and cause kidney failure.

This is why E. coli O157: H7 is considered so dangerous. Young children and the elderly are particularly vulnerable.

Of course, scientists are studying pathogenic E. coli like E. coli O157:H7 right now, to figure out how to best combat it.

Not as well-known is E. coli's role in the history of molecular biology. E. coli is widely used as a model organism - that is, by studying it in detail, scientists can make general conclusions about the genetics of other organisms. In fact, some of the biggest advances in genetics were accomplished by using E. coli.

By studying E. coli, scientists gained insight not just into bacterial genetics, but also genetics for all organisms.

For example, the scientist Seymour Benzer used E. coli to demonstrate that genes were divisible units, thus confirming Watson and Crick's model of genes being made of many parts. Some still say that Benzer should have received a Nobel Prize for this discovery.

As I mentioned earlier, E. coli is an inhabitant of the digestive system. Millions of E. coli are expelled along with feces.

Therefore, the most obvious way for E. coli to get into your food is if it is contaminated with fecal matter or other material from the digestive system.

You might say,"I'm not going to eat food that has poop on it!" Well, neither am I! But I'm afraid it's not quite that simple. See, all it takes is microscopic amounts of fecal matter in your food, which you won't be able to see with your naked eye.

And if you think about it, fecal contamination really isn't that uncommon. All it takes, for example, is for someone not to clean their hands after using a bathroom, and then handling food.

Also, fecal matter may come from a cattle farm near a vegetable farm - the E. coli from the feces of the cattle may eventually make its way to the vegetables by run-off all other means.

This is an excerpt from an FDA report on the 2006 E.coli outbreak in spinach.

"(...)samples of cattle feces on one of the implicated ranches tested positive based on matching genetic fingerprints for the same strain of E. coli O157:H7 that sickened 204 people."

In other words - the same strain of E. coli in the spinach fields was found in cattle feces. This shows that spinach fields may have been contaminated with feces - one of many ways that E. coli can get into your food.

E. coli can be found in the digestive systems of cattle. When cattle are slaughtered, E. coli can get onto meat from the digestive systems.

And then, when the meat is ground, any E. coli present in it becomes thoroughly mixed throughout the meat.

This contaminated ground meat is then made into the burger patties that goes into your hamburgers.

E. coli O157:H7 can get into any food through fecal contamination.

In the past, E. coli O157:H7 outbreaks have been associated with the following foods:

Apple Juice
Alfafa Sprouts
Ground Beef
Lettuce
Raw (unpasteurized) milk.
Spinach
Water From Wells

I recommend the following steps.

Cook beef to at least 160 F (71 C). This includes burgers, folks - and yes, use a thermometer. That's the only reliable way of checking to see that the burger is cooked thoroughly.

Wash your hands and all utensils that touch raw meat, with hot water and soap. E. coli can spread through your hands, too! And be sure to clean the faucet before you turn it off, because if you use your clean hands to touch a faucet contaminated when you touched it with dirty hands, you've just contaminated it again!

Do not mix raw meat and stuff that's ready to eat, like vegetables. Do not use the same plates and utensils for raw meat and other food.

Drink pasteurized milk and fruit juices, and water that comes from a safe source like the tap. Avoid drinking river water and other unsanitized forms of water.

If you get a burger that's undercooked at a restaurant, return it. And ask for new buns, vegetables and serving plate as well, because the might have been contaminated by the raw meat.

In general, you can take really simple steps to dramatically reduce your risk of getting sick from E. coli!

As you can see, while E. coli can be a dangerous organism, in reality, it's much more common than you think, is usually harmless, and has made great contributions to sciences. But I've really only scratched the surface of what we know about E. coli - if you want to dig deeper, check out the book recommendation below!

As always, be sure to take the proper precautions so that the only E. coli you have are the friendly ones!

(And feel free to leave any corrections, comments and feedback down below. :) )

1. CDC: Escherichia coli General Information.
2. CDC: Escherichia coli O157:H7 and Drinking Water from Private Wells
3. CDC: Outbreaks of Escherichia coli O157:H7 Infection Associated with Eating Alfalfa Sprouts -- Michigan and Virginia, June-July 1997
4. CDC: Questions and Answers about E. coli O157:H7 Outbreak from Fresh Spinach
5. CDC: Questions & Answers: Sickness caused by E. coli
6. CNN: 21.7 million pounds of beef recalled
7. CNN: E. coli poisoning leads to Odwalla juice recall
8. CNN: Still no answers in '06 lettuce E. coli outbreak
9. FDA: Nationwide E. Coli O157:H7 Outbreak: Questions & Answers
10. LA Times Obituary, Seymour Benzer