[USCC] FW: Re: Fecal Coliform testing issues

[Tim Evans]

Frank

In a large research program 
UKWIR (2000) Methods for detection of pathogens in biosolids.  Report ref.
00/SL/06/05.  UKWIR, London 
UKWIR (2002) Pathogens in biosolids the fate of pathogens in sewage
treatment.  Report ref. 02/SL/06/6.  ISBN: 1 84057 2612  UKWIR, London
UKWIR (2003) Pathogens in Biosolids - Microbiological Risk Assessment.
Report ref. 03/SL/06/7.  ISBN: 1 84057 294 9 UKWIR, London
we found E. coli O157:H7 was no more resistant to composting and other forms
of treatment than other indigenous E. coli.  Cultured lab strains were
different - they were more susceptible to treatment.  

However, since the infective dose of O157 is so low for humans and the
effects so dire my approach (consistent with HACCP) has been to look at the
source of material being treated.  If it is animal manure (cows or sheep)
the chances that it contains O157 are high because a high proportion [10%?]
have symtomless infection and are shedding log-8 per gDS.  I would therefore
be very careful about the treatment if the product of treatment is going to
be handled or to be in contact with ready-to-eat crops, etc.  If I were
starting with manure and the product was intended for a 'high risk' use, I
would validate the process by testing for O157 - for broad acre agriculture
(grains, etc.) it is not really an issue because there is a second barrier.

regards
 

Tim


-----Original Message-----
From: frank [mailto:frank at compostlab.com] 
Sent: 07 November 2006 18:54
To: US Composting Council Compost Discussion List
Subject: Re: [USCC] FW: Re: Fecal Coliform testing issues

Tim,
HACCP system with the control points along the way you describe seems 
like a good system. The composter could take the temperature readings 
during the process and then test for fecal coliform at end of the heat 
cycle to varify the material was well mixed and heated throughout the 
pile. If it does not pass it is up to the composter to find a way to get 
the heat high enough and mixed so it will. As it is now the composter 
doesn't know where the problem is to even start work on it. It could be 
poor heating or poor mixing or even re-growth during the final stages of 
stabilization or curing - nothing to do with pathogen kill.

And, like what is happenng in my back yard with the E Coli scare, it 
should be the industry that regulates itself and sets the rules. That is 
what I thought the USCC would do because it is made up of all the 
players and has all the experience and expertise to establish a good 
system.  Its true, as Eliot says, we can do nothing about the EPA  
regulating biosolids compost at point of sale, but we do not need to 
require the other forms of compost to do the same and we can regulate 
metals lower than EPA and catch problems 'before' they happen. We can 
set our own rules. The USCC should set the industry standards, IMO  
Also, if we (UUSCC) believe E Coli 0157 could be a problem (like 
copyralid) we could require it be included in with the testing until it 
is shown to not be a problem, or need corrections before it becomes a 
problem. Last thing the industry needs is a problem with E coli 0157. If 
we don't take the lead someone that knows nothing about composting will.


Frank




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