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  • From: KAKerby AT aol.com
  • To: market-farming AT lists.ibiblio.org
  • Subject: Re: [Market-farming] manures/GAP training
  • Date: Tue, 2 Mar 2010 17:27:32 EST

The science behind the new guidelines were based on recent studies which have tracked how long E. coli lived either in the soil or on surfaces.  They provided details from one of the studies, which tracked soil, onion and carrot contamination, on four test plots per vegetable along with a control plot.  If you want the exact name and authors of the study, I can provide that but the title was pretty long.  Those results were published in the Food Microbiology journal in 2005.  In that study:
1) After the soils were innoculated, they then watched to see how long the populations would live in the soil, along with carrots and onions grown in the soil.  With the population numbers on a graph, the numbers stair-stepped down a few times throughout the experiment but quite a few were still alive at Day 120, with those final holdouts dying off between Day 180 and Day 205.  Furthermore, carrots and onions harvested from that soil continued to have viable E. coli survive on the surface of those roots for another long period - carrots harvested on day 126 still had viable E coli on them on Day 168.
 
2) Only 10 E. coli cells are sufficient to cause illness in human beings.  So having even extremely low counts still alive in the soil can provide for a 'bloom' later if the right conditions are met.
 
3) E coli is extremely mobile in irrigation water, which means that any soils containing E coli which are splashed or sprayed onto crops can carry the E. coli to any wetted surface.
 
Someone asked whether the organic standards would be changed to reflect these findings.  The WSDA Organic Certification staffer replied "I sure hope so".  When the WSDA scientists were asked whether these policies were going to eventually move from being guidelines to being requirements, they replied that regulatory action may never occur.  But they also pointed out that large-scale buyers such as Walmart and Costco are already putting requirements like this into practice from the farmers and brokers they buy from.  Once those big-box buyers make decisions like that, the smaller grocers and other retailers quickly follow suit.  The WSDA staffers said once the bigger retailers all jump on that bandwagon, these guidelines economically become a requirement even if they are not yet a regulatory requirement. 
 
These are still "suggestions", to be sure.  And perhaps they always will be.  But the reasons for what they're recommending seemed pretty straightforward to me.  Having watched a few illness cycles bring down producers during past E. coli scares, I'd like to be able to look my customers in the eye and say 'yes, I am familiar with the risks and yes I take best management steps to minimize that risk.'  I've been asked that before and I'm not going to stop answering that question now.  If we didn't rely so heavily on animal manures and composts here to maintain soil fertility, I probably wouldn't be quite so interested.  But using those tools I felt the need to be respectful of when they can create problems.
Kathryn Kerby
Frog Chorus Farm
Snohomish, WA
 
In a message dated 3/2/2010 12:36:37 P.M. Pacific Standard Time, organic87 AT frontiernet.net writes:

On Mar 2, 2010, at 10:14 AM, KAKerby AT aol.com wrote:

Regarding the statement below about manure-to-harvest intervals, I'd be curious to know how many folks on this list have attended GAP training, and/or how many people are putting GAP into use.  When I attended an intro session here last month, the recommendation is now 210 days between application of manure and harvest of ANYTHING - roots, leaves, fruits, whatever.  That sure set us back.  We decided that knowing the new guidelines, we couldn't in good conscience expand into a field that would clearly fall between the old 125-day and new 210-day withdrawal period.  One whole field of production - removed from consideration in 2010.  Anyone else weighing those options?
Kathryn Kerby
Frog Chorus Farm
Snohomish, WA
 

Do they have any science whatever behind those recommends? 

I haven't been to GAP training: the only sessions I've seen offered take two full days plus travel time and hotel room as they're nowhere near here, and I'm not selling through any route that requires this. (I have downloaded and will look through some of the National GAPS materials from the Cornell.edu web site.) 

I was just at a discussion meeting for proposed FDA produce handling standards, and I didn't hear anything there about increasing the manure intervals. I did here (there and elsewhere) that some private GAP programs may be requiring things that are likely to do no good and very likely do considerable harm.

Do you actually need GAP certification for your particular 2010 expected sales methods? and, if so, do you need to get it through that specific program? If not, I'd think twice about not using the field because of a statement made at that one session.


-- Rivka; Finger Lakes NY, Zone 5 mostly
Fresh-market organic produce, small scale



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