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Re: Proper compost
Hi Roberto -
I am speaking from the USDA organic program point of view. As Elliot Coleman just pointed out to me (and he's right), the USDA really pushes thermal composting. There are other ways to arrive at the same E. coli-free conditions, such as cold-composting methods. At least worm compost has been recognized this time around in the USDA regs. That is a good addition. But there are other composting methods the USDA still left out.
From a food safety point-of-view, compost needs to be E. coli free. For compost tea purposes, compost needs to be E. coli free.
As I've said before, E. coli is an indicator of the presence of other human pathogens. If E. coli is not present, most likely the human pathogens are not present either, because the human pathogens, like Salmonella, Shigella, Yersinia and Pasteurella have similar requirements for growth and survival as E .coli. If E. coli is present, sooner or later, you will have a human pathogen present, and the likelihood for disease significant.
The question previously was whether properly composted material would contain E. coli. For thermal compost, if the growth of the organisms in the compost raises the temperature to high enough levels, for long enough, under aerobic conditions, then E. coli will not remain. Simple. How do you document compost quality? Testing.
Many people do not understand that the bacteria and fungi growing in organic matter raise the temperature. If all you do is physically heat compost, you don't get the same reduction in E. coli. This is a biological process. Competition with aerobic bacteria and fungi, inhibition by other bacteria and fungi, and consumption of disease-organisms by protozoa and nematodes are all part of the process of making good compost, getting rid of the pathogens.
If you just steam heat organic matter, you don't get the same benefits of the growth of the competitive, inhibitory and consuming interactions that happen when the full food web is present.
So, to document that compost has been properly composted, you have to do the testing. But once you know that your mix of starting materials, the temperatures and the turning that result in a good compost, then you just have to monitor starting materials and temperature. Check your end-product now and again for biology and chemistry.
The thermal method pushed by the current USDA-NOP regs is hot and fast, and can make "finished" compost in 6 to 8 weeks. But not everyone wants to do that.
Can't you make good compost in 5 months without high heat? Yes. But that approach is not included in the NOP regs.
Does that mean long-term, cool compost isn't compost? No.
How do you know if quality compost has been produced? Organisms. Chemistry. No E. coli, and all the good guys.
Once you have the process worked out, and can show it works every time, then you just track temperature. Do we have the longer process worked out? We're working on it. Will E. coli be removed everytime? So far so good. What are the important components? The right starting materials, aeration and the correct organisms. Turning is not required, if you make the pile right.
This is the approach that Edna wants. Can we get it certified organic?
If you make your own compost, and you mess up, and you get sick, you won't sue yourself. If you sell to other people, and they get sick, you better get ready to lose your shirt, cause those folks are going to have your hide.
So, the regs really are for people who sell products to other people. If you aren't selling things, do you need the USDA regs?
President, Soil Foodweb Inc.