[USCC] O157 E Coli

[Tim Evans]

Alan,

The extensive UKWIR research
http://www.ukwir.org/site/web/content/reports/reports?SubFolders=90083&Folde
rId=90078&SubFolderId=90083 showed that E. coil O157 has a similar
thermo-tolerance to indigenous E. coli.  This was a big concern because
there had been reports that it was more thermo-tolerant than "normal E.
coli" but this was proved to be wrong - the earlier researchers had used a
cultured laboratory strain as their reference and because of its "pampered"
existence this culture was less thermo-tolerant than indigenous E. coil -
i.e. the stuff that we healthy animals excrete every day.  The research also
confirmed indigenous E. coil is a good indicator for other bacterial
pathogens and that using such as Salmonella Senftenberg is unnecessary -
indeed I can't see how the conditions inside a microcosm used to contain the
S. Senftenberg can possibly mimic conditions in the bulk of the material
being treated.  

I agree with the 503 Class-A and Class-B standards and used them before
there was anything comparable this side of the Pond. However there is also a
question of diligence - the dung from an animal infected with O157:H7
contains up to log-8 E. coli per gram dry solids.  The infective dose for a
human [with low defence] is 10[?].  If I was treating manure that could have
O157 I would look at the intended use [and the reasonably expected misuse]
for the product.  Thankfully, a tiny minority of humans have O157 infection;
the same cannot be said for farm animals so that is why I would be more
cautious with manure than sewage sludge.  

When, in 1995, I embarked on bagging biosolids composted with straw and
selling it to gardeners via garden center retailers, I was concerned to meet
the highest standards and we used Class-A / PFRP.  We gave hygiene
instructions on the bags about handwashing but it is reasonable to expect
some will ignore this.  Also children might be around it.  We had a QA
system for time temperature and sidelined any that did not meet it - this
went to broad-acre agriculture small-grain cereal production.  We verified
the QA time-temperature with E. coli testing - to verify that the Critical
Control Point's Critical Limits were appropriate.  But, this was a 'high
risk' use so Class-A was essential. [we could have labelled, but didn't
"when you have handled chicken, please wash your hands before touching my
compost" -:) ]

On a note of good news, Protozoa in soil love gram negative bacteria so when
the E. coli, Salmonella et al. land on soil the Protozoa think "it's
breakfast time", graze them and multiply. 

regards

Tim


-----Original Message-----
From: The Rubins [mailto:rubinhial at cox.net] 
Sent: 17 December 2006 13:51
To: US Composting Council Compost Discussion List
Subject: Re: [USCC] O157 E Coli

Forrest and Tim:

Am I missing something in this discussion?  The USEPA Part 503 Standards for

the composting of biosolids result in the reduction/elimination of 
pathogenic microbial species in the finished biosolids-based compost to 
levels where the compost is perfectly safe to handle as an agricultural, 
horticultural, or lawn and garden product without any further regulatory 
restrictions.  Surely neither of you is suggesting that the pathogenic 
strain of E Coli, O157, is some sort of a super thermophile, able to survive

under the Part 503 Standards' thermal and aerobic composting conditions??

Or are you suggesting that somehow the presence of E Coli O157 in animal 
manure (not biosolids) is somehow immune from destruction under Part 503 
conditions?

Or is it just that the composting conditions that Forrest is using is not as

rigorous as the Part 503 Standards?  Please clarify or comment on this. 
Elliot and Rufus, your comments are welcome and needed as well.

Cheers

Alan


----- Original Message ----- 
From: "Tim Evans" <tim at timevansenvironment.com>
To: "'US Composting Council Compost Discussion List'" 
<compost at composter.com>
Sent: Sunday, December 17, 2006 2:44 AM
Subject: Re: [USCC] O157 E Coli

> Forrest,
>
> Yes, goats can carry O157:H7.  The food safety newsletter Fsnet just 
> carried
> an article about a 17 year old girl who came down with O157 after stroking

> a
> bottle-fed goat kid that was taken to her church - the story said that 
> after
> stroking the kid she went on to suffer kidney failure and had a leg
> amputated because of gangrene.
>
> Whether to compost animal manure is a risk assessment:
> - is there a pathway for direct ingestions such as will people be handling
> the compost with their bare hands?
> - will it be used on soil in which plants will grow that will be eaten 
> raw?
>
> If I were going to use the compost on corn crops, around top-fruit or
> ornamental plantings (as examples) I think I would include the manure in 
> the
> composting - but it's your decision - you know what the compost is going 
> to
> be used for and how controlled your conditions are.
>
> regards
>
> Tim
>
>
> -----Original Message-----
> From: Forrest W. Thye [mailto:thye at vt.edu]
> Sent: 14 December 2006 19:41
> To: compost at composter.com
> Subject: [USCC] O157 E Coli
>
> I have seen E Coli O157 mentioned to be wide spread in cattle and
> sheep manure (and pig manure who have consumed cattle or sheep
> manure).  Is O157 found in horse or goat manure as well and as wide
> spread as in cattle and sheep?  Since I don't have the facilities to
> compost with the control needed to be sure to kill pathogens such as
> O157 I don't think I should be using any manure from any species in
> my small scale composting operation.  Thanks
> Forrest Thye
>



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