Re: E.coli

From: Elaine Ingham (Soilfoodweb@AOL.COM)
Date: Mon Nov 04 2002 - 05:22:40 EST


Ok, let's go over this again.

E. coli out-competes other organisms only in reduced oxygen conditions. If
E. coli actually could out-compete aerobic organisms, then it would NOT be
useful as an indicator of human pathogens. Human pathogens require the
conditions in human digestive systems in order to grow - lack of oxygen is
important. Can you grow Salmonella aerobically? Sure, in the lab. But for
Salmonella to survive and grow in food, to give food poisoning problems, the
temperature of the food has to be warm enough, but not too warm, which means
oxygen in the food is limited AND competing organisms are limited.

PLEASE, understand that microbiologists are missing the point when they say
that E. coli can grow aerobically. It does happen, but ONLY IF competing
aerobic organisms are not present. Very particular growth conditions are
required. You must select against the growth of other aerobic organisms.
So, in the lab, the right temperature, rich medium, often antibiotics, and NO
SIGNIFICANT NUMBERS OF COMPETING BACTERIA are all required to grow E. coli in
fully aerobic conditions.

That's what most laboratory, not-familiar-with-the-real-world,
work-with-only-one-species-at-a-time microbiologists don't understand.
Competition is important in the real world.

If you want, you can ask whoever is saying E. coli grows aerobically where
their scientific data are, and I'll be happy to point out where they are
missing the point.

The head of the composting program at the USDA in Beltsville visited me once
and mentioned an experience where composted manure was tested and E. coli was
not detected. They put the compost out into a field, and a few days later
detected E. coli. This person used that example to say that E.coli can come
back to life in compost.

Really? Ask the appropriate question: Were there E. coli in the field soil
BEFORE they added the compost? No answer to that question when I asked it.
I have never seen that paper published either, although I must admit to not
particularly looking for it. It may have gotten past reviewers who don't
know much about holistic systems.

Here's another example - We take cultures of E. coli and dump them in soil.
If the soil has a healthy foodweb, you will not detect E. coli in 24 hours.
Ah, but if the soil is not healthy, and lacks good structure, you can detect
E. coli for many days.

It's the NORMAL life that is important. If there are no competitors, no
consumers, no inhibitors, then E. coli may do ok.

Think about your hands. Every time you visit the bathroom, you potentially
pick up E. coli. But you aren't swarming with E. coli. Washing your hands?
But that's just soap, why would that kill E. coli? You have lots and lots of
bacteria and some fungi on your skin surfaces, and they compete with, inhibit
and consume E .coli. Only if you are sick, and something severely disrupts
the foods your skin puts out to feed the beneficial bacteria and fungi, will
E. coli be able to survive, and maybe even grow.

If E. coli survived as well in aerobic conditions as it does in anaerobic, E.
coli would not be useful as an indicator of human pathogens. What would kill
E. coli in the real world, if it could grow just as well aerobically as it
does in reduced oxygen conditions in your digestive system? E. coli would be
everywhere, but it isn't.

Why?

Elaine Ingham
President, Soil Foodweb Inc.
www.soilfoodweb.com


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