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Re: Compost Tea
There have been questions about the National Organic Program regs on compost tea, so let me offer some perspective.
The National Organics Standard Board appointed the Compost Task Force to write the regs on compost. The task force was also given the task of writing the compost tea regulations.
Apparently, the Compost Task Force chairperson, Eric Sideman, called two people, Wil Brinton, and Pat Milner, and on the basis of their opinions, wrote the regs on compost tea. Initially, the recommendation said that sugar, molasses, barley malt and soluble carbon materials could not be used in compost tea, because E. coli would grow if these materials were in the tea.
Why was this reg put together? Where did that come from? Is it meaningful?
First of all, who are Wil Brinton and Pat Milner? Wil had given up on 3-week anaerobic compost teas because he could never get rid of the E. coli. Pat Milner has never made compost tea, that I am aware, but had funded two studies on compost tea. The studies were performed at the USDA lab in Albany, CA by a student of Dr. Subbarao's, whose background is in the pharmaceutical industry, and the second study was done by BBC Labs, run by Ms. Vicki Bess, who has a Master's degree in microbiology. Neither has experience with 24-hour compost tea.
Dr. Subbarao's student, Brian Duffy, took E. coli-containing organic matter (compost can't have E. coli under the USDA NOP regs, so it wasn't finished compost. And according to the source of the "pre-compost material", it wasn't finished compost). The E. coli-containing material was placed in flasks, the flasks sealed and incubated for 24 hours. E. coli was detected in the material they sprayed on plants the following days.
This study has nothing to do with compost tea. No compost tea maker is sealed shut. No one makes tea that way. There is absolutely no evidence here that aerobic compost tea could cause a problem. This was a study that was a waste of tax-payers' money.
BBC Labs took the same E. coli containing material, put it in a Growing Solutions machine that always goes anaerobic in the basket during the tea making process, added sugars, molasses, and barley malt, and found E. coli growing in the 24 hour brew.
First, the "compost" contained E. coli. Second, this particular tea machine always goes anaerobic in the basket, and thus sets the stage for the growth of E. coli, because the E. coli can out-compete the aerobic, beneficial organisms when oxygen is low. Third, the addition of sugar, molasses, barley malt probably got the bacteria growing so rapidly that they used up oxygen which helped the E. coli out-compete other organisms.
The paper published by BBC Labs in Biocycle (not a peer-reviewed journal) had data on temperature and oxygen. The temperatures cited ranged from 21 to 27 C. The oxygen concentrations reported by Ms. Bess were between 10.1 to 10.9 mg oxygen per liter.
It is NOT POSSIBLE to have these levels of oxygen in water at the temperatures cited. Consider too that the elevation of Tempe, Arizona means the oxygen concentration is even more impossible. Check the maximum concentration of oxygen in water on the US Geological Survey website. These concentrations are NOT POSSIBLE at these temperatures and elevations. Unless the air was pressurized, and there is no mention of that in the paper. Water holds less oxygen as temperature, or elevation, increase.
I contend that Ms. Bess did not in fact measure oxygen in the tea brew that BBC Labs reported on. The oxygen data were probably from work done by the manufacturer, in Oregon, in the winter, at basically sea level. The oxygen data fit Oregon winter conditions.
There are no data to support Bess' contention that the tea stayed aerobic through the whole brew cycle. But there's no way to know, actually, because they could not have measured the oxygen on the tea run where E. coli occurred.
Thus, the "data" on which the Compost Task Force based their recommendation were flawed. With or without sugar, molasses or soluble carbon materials, there was no evidence that E. coli would occur in tea. All our data indicate that as long as tea is kept aerobic and numbers of bacteria and fungi are high and actively growing, no E. coli will be detected, or only at very low levels. All tea machines that get good fungal growth must remain aerobic.
I have been told that Vicki Bess says that the Growing Solutions tea maker "super-saturates" the water with oxygen. If that was true, then E. coli would not have been detected, because E.coli cannot withstand highly oxidizing conditions. In fact, no one I know who owns the Growing Solutions tea maker has obtained the high oxygen concentrations that the manufacturer shows on the web site.
There's a serious discrepancy here. Until someone else can repeat the same results, i.e., show the tea maker stayed aerobic through the tea brew, and E. coli was still in high numbers at the end of the brew, this study has to be viewed as not scientifically sound.
Ms .Bess says that she has data showing that E. coli grows in aerobic conditions. E. coli can grow in aerobic conditions in the LAB, where we grow the organism in very specific conditions that allow E. coli to grow in aerobic conditions. If there are a reasonable number of aerobic organisms present, E. coli will be out-competed for food and space. Protozoa in the tea will consume E. coli. In aerobic conditions, with high numbers of competitors, predators and inhibitory compounds produced, E. coli does not survive.
If E. coli did grow in aerated conditions found in sewage treatment plants, E. coli would be everywhere, on everything. But it is not, so clearly, aerobic conditions, with lots of competitive, inhibitory and consuming organisms present, will take out the E. coli.
Why do we get concerned about E. coli? Because if E. coli is present, it means there is contamination by fecal material where sooner or later there will be a human pathogen present, and then we have disease. So, E. coli is an indicator of a problem, not something to go nuts about. There's a problem, work to fix it.
Pathogenic E. coli is not likely to occur if healthy animals are making the manure. It is much more reasonable to make a regulation about the kind of manure that can be used, that testing of the compost has to be done to document no E. coli, or that the tea brew has to stay fully aerobic so E. coli is taken out than say all compost tea is dangerous.
Do we have data showing that E. coli does not survive in aerobic conditions? Yes. We submitted that data to several people who were at the NOSB meeting. Did they present that data? Not that I'm aware.
A week before the NOSB meeting, Wil Brinton sent an e-mail to the email@example.com list serve. He basically told us about the deal he had tried to make to keep compost tea in the NOP rules. The ruling about sugars came from him, apparently. If that rule had been adopted, we would not have been able to put compost in the compost tea, because compost contains soluble carbon materials.
So, it was a non-choice. That poorly written, not-supported-by-the-data recommendation had to be removed. But what was it replaced by?
Wil Brinton apparently decided that compost and worm compost tea cannot be used on foodstuffs because of the possible danger that E. coli may be present. But there is no evidence to say there is a danger with properly made compost tea. All they had to put in a regulation was that compost tea made from compost without E. coli present in the compost was acceptable. If made with E. coli-containing materials, the tea had to be kept aerated, and have plenty of competing bacteria, fungi and protozoa. We have documented the reduction in E. coli, and thus in any human pathogen, in properly made compost tea.
For the NOSB to accept a recommendation based on incorrect studies, studies to peer-reviewed, not published in any scientifically peer-reviewed journal, using only one poorly designed tea machine, or sealed glass flasks, is just unbelievable. The data on sugars causing E. coli to grow in aerated tea is silly. The data in the paper clearly show that the oxygen data are not correct. It is very likely that the tea did not stay aerobic.
We have repeated a number of studies showing that E. coli does not survive in aerated tea with adequate competitive life. Starting with "composted" manure with an average number of 44,000 E. coli per gram of manure, the E. coli present at the end of an incubation with molasses and kelp in the brew, was 2.7 E. coli per ml of tea.
This is less than E. coli levels allowed in irrigation water, and irrigation can be done up to the time you pick your crop. Why is organic agriculture being held to a higher standard than conventional crops?
The development process for National Organic Program regulations has been poor. The people appointed to write the recommendations did not do their jobs in a number of cases. A conversation with two people who don't have expertise on 24 hour compost tea wrote the regulations? The Compost Task Force should have researched the conditions that allow E. coli to grow, and should have known that anaerobic, or reduced oxygen conditions, are required for E. coli to grow and survive. Aeration result in the death of E. coli. High oxygen concentrations kill E. coli. Talk to sewage treatment people.
We were almost saddled with a really stupid regulation about no sugar in tea. Then instead of doing their job once the first objection to the lack of science forced them to rescind the recommendation, they wrote a regulation that compost tea can't be used because of the fear of E. coli.
I can put manure in coffee makers, and make a brown liquid that looks like coffee. Is anyone suggesting that coffee makers should be dis-allowed because someone could be stupid and put the wrong stuff in a coffee maker?
Of course not. The regulations should be written to state the conditions that allow safe compost tea to be made. Aerobic through the whole brew cycle. Lots of good aerobic bacteria, fungi and protozoa growing to compete with, inhibit and consume the E. coli.
That gets rid of the E. coli and human pathogens.
If there is no E. coli in the starting materials, then why say there's a danger of E. coli. At least compost tea made with non-manure materials should have been allowed.
But no, no tea at all can be used.
Anyone else feel like there's a hidden agenda here?
President, Soil Foodweb Inc.
Director of Research, Soil Foodweb New York
President, Soil Foodweb Institute, Lismore, Australia
Director of Quality Assurance, Soil Foodweb Europe, The Netherlands