Peter T. Holman pholman at perrittlab.com
Tue Nov 4 12:44:01 EST 1997

	It is expected that you will find coliforms in your control samples.  They
can come from birds, deer, etc.
	The dampness of the ground can allow more organisms to survive because
they won't dry out and die.
	The test for fecal coliform simply means that the incubation during
testing was at a higher temperature 45C vs. 35C.  The results are suposed
to be fecal assuming that mammals have a higher body temperature, and
coliforms in their fecal matter will be used to the higher temperature. 
The results are less than exact. 

	Coliforms are indicator organisms of fecal contamination in water.  It is
not really the coliforms themselves we are concerned about - it is the
potential for other pathogens to humans present in human fecal matter.  The
anal-oral route of infection.  We look for coliforms because it is easy
when looking for specific pathogens can be quite difficult.

Hope this helps,

Peter Holman
Senior Research Microbiologist/QA
Perritt Laboratories, Inc
Hightstown, NJ  USA
pholman at perrittlab.com

edesign at powerup.com.au wrote in article
<345b2553.127635119 at news.powerup.com.au>...
> Hello Folks,
> I recently had a microbiologist take some samples around my house, (we
> have a Greywater recycling system and composting toilet) and he found
> a level of faecal (fecal) coliform bacteria around the site between 22
> and 1700 organisms cfu/g (Wet Wt.) Method 4.409 MPN. The samples were
> taken from the soil  in a heavily mulched and damp garden bed where
> the Greywater is used for irrigation.
> At two control points outside the yard he found 27 & <2 (is that 1?)
> cfu/g. The soil he took the control samples from was very dry, hard
> clay. I asked him what he expected to find in the control samples and
> he said there might be something (bacteria) and that there would be
> more if it was wet.
> The 2 control samples were taken from places that were up stream from
> the Greywater recycling.
> A few questions and THANK YOU in advance if you can shed some light or
> point me at a TEXT I could use.
> 1.  Were might the 27 faecal (fecal) coliform bacteria have come from
> that were in the one of the control samples.
> 2.  If the ground was wetter what might be the population cfu/g of
> naturally occurring coliforms.
> 3.  Are the testing procedures used reliable at picking up just faecal
> (fecal) coliform bacteria or do they pick up other bacteria in the
> soil?.
> Hope you can help. Please drop me a line.
> Jonathan Berry
> ECO DESIGN Sustainable Housing.
> Ph -  61-7-3848-0846,Fx -  61-7-3848-0548
> Email: edesign at powerup.com.au
> http://www.powerup.com.au/~edesign

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