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I have been made aware of a section in the latest newsletter of an aquaponics trainer making some rather interesting statements around the risk of introducing "deadly" E. coli HO157:H7 into aquaponics systems through the introduction of worms.


Like most promotional material, it contains enough reference to some form of correct base statement to make their argument appear compelling, but I have found the way that the section was written distressing in many ways.  On one front, we are trying our level best to ensure food safety and hygene in our units and to educate people on the safety of aquaponic production methods.  To have someone from within the community write something down the line of "if you dare put worms in your system you run a very real risk of introducing a deadly pathogen into aquaponics" is not conducive to building a fair and realistic impression of aquaponic production methods.  Worms in media beds have been in use for many years outside of the design of the group in question, with no reports of any health issues.


The inference made was that (without stating how many worm growers use cattle poo) red wrigglers are likely or potentially all grown in manure from corn fed cattle and this all contains the "man made" (?????!) strain of E. coli that will then most likely survive the transfer from worm to your system where you will contaminate your crops, your family or your customers.  If you are extra unlucky, a fly from a pasture containing corn fed cattle poo will also do the trick (then why bash the worms?) if they can make the trip in under 10 seconds. 


The article would have had more use if it simply said something down the line of "pick your worm supplier carefully - if you are cautious about E. coli, steer clear of using worm growers that cannot guarantee that their worms were not fed corn-fed cow poo from feedlots." I do not know what the ratio is of worm producers that potentially use this feed method compared to those that do not, but if it is the case that very few follow this practice, this article borders on reckless.  Then one can write follow-ups warning people on the next one in a gazilion risk such as a bird-flu contaminated duck landing in your fish tank.  As stated before, in theory, the conditions described in the text can potentially occur. Just as, in theory, a monkey can sit down in front of a typewriter, hammer away at it and write something recognisable. Not impossible, but likely? 


I wrote a blog a while ago about the responsibility of perceived role models in the industry related to statements made and perceptions created from a "credible" source.  This type of statement was exactly what I was talking about.  Not worth the negativety and not worth the potential bad press and poor PR for what many aquaponic producers see as a staple - media filled beds with worms in them (is there a reason for this?).  As a scientist, I would like to see some concrete evidence related to instances of the scenario described having been observed at worm farms and in aquaponic systems.  If no such data exists, is this statement fair and accurate? Why was it made? I do not want to appear to downright rubbish their concerns, but I will appreciate a percentage risk description to back up this claim.

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While we have all this wonderful discussion about wonderful worms, I thought Sylvia's latest blog post, "Aquaponics and the Wonderful Worm" should be included!  Here ya go!

Gina by the way, I just took delivery of my worm farm yesterday. Thank you amazon!
Sylvia, thanks. Hence all my apologies before, I really wasn't sure what would be a tidier way to have it done. Thanks!

Sylvia Bernstein said:
Hi Nigel.  I hope you don't mind but just to keep things a bit tidier in here I'm posting the link and deleting that novel!  Thanks

Nigel Clement said:

Not sure how to link it, I'll paste it in here. If it is too long I do truly apologise.


 Sylvia wrote a very nice blog post... Thanks for posting the link!


  I am completely confident in using redworms in an aquaponic system. Yup, I'm the "professional worm wrangler" Sylvia mentioned in her blog post.

 I have another "can of worms" to introduce...or mostly it is a question for those who are in-the-know.  I am learning about BSFL to use as live fish feed for aquaponics systems.   Do all of you wash off your BSFL before feeding them to your fish?  I'm just wondering if this would not also be another source of possible contamination if not handled properly? Such as plopping in the BSFL  in the tanks with food matter/yuck on their bodies.  I know I read somewhere that these guys also "clean up" bacteria (can't remember the source, so do I do not remember if this is reliable - I am very careful that info. I use is from reliable sources -so please correct me if this is not accurate.  Or can anyone supply me with research link supporting this?).  Not trying to sideline this discussion.  Just think this might be a valid concern as far as places contaminants can be introduced into an aquaponics system.  Please let me know, for those of you who are in-the-know.

    Is that a collective groan, and a "here we go again" sigh?    Please be kind.  I really want to know.

From what I've read here, it seems that as careful as we all may be, there is still a chance that our systems may become contaminated with deadly germs. So rather than add to a list of extremely remote vectors of transmition, I think it's high time to introduce some vectors of germ control. From what I've gathered, these controls are: heat above 170 , sunlight, aerobic microbe competition, composting worms, and time. Other than heat, all those control vectors are cultivated in aquaponics. Perhaps that is the reason that germ problems are rare. Actually, has there ever been an outbreak from any AP system?  I would like to see an experiment where an AP system was intentionally cultured with E. coli, and worms, water, plants, and bioslime regularly tested to see how quickly the threat is eliminated. 
Ahhhhh Jon now we're talking about a control system and an experimental system? This is getting good!
You are very welcome, Nigel   Love it, Jon.  Excellent point and I'll bet the results would be very favorable....but without a formal test of all these elements together we will never know.  Someone was saying earlier that there had never been a reported case of a disease coming from an AP system...but we are still so new I"m not sure that means much yet.  Oh, and thanks Converse for supplying excellent blog fodder! ;-)

Nigel Clement said:
Sylvia, thanks. Hence all my apologies before, I really wasn't sure what would be a tidier way to have it done. Thanks!

Sylvia Bernstein said:
Hi Nigel.  I hope you don't mind but just to keep things a bit tidier in here I'm posting the link and deleting that novel!  Thanks

Nigel Clement said:

Not sure how to link it, I'll paste it in here. If it is too long I do truly apologise.


A few more thoughts on the subject, in any commercial system a HACCP plan (Hazard Analysis critical Control Point) should be written. In a properly written HACCP plan the subject of the potential addition of pathogens through the addition worms  would be covered and controlled. I personally believe a HACCP plan should be written covering  any potential food safety concerns for all commercial operations.  HACCP is mandatory for the Meat industry but the problem with that is that it’s mandatory. Instead of actually going through the HACCP process many meat plants just wrote plans to meet the basic requirements to meet the Mandatory requirement, not all but some. HACCP is a great tool and should be used especially since we are a new industry, we should be at the fore front showing our products and growing methods are as safe as and safer than any other natural growing method today. I truly believe Aquaponics is the safest natural growing method available today; it’s up to us to prove it!

Ok. Im off my soap box now

Although I have heard of HACCP plans and no doubt the concept has merit, what worries me most is GAP certification (Good Agricultural Practices). We have a very active county agricultural development group here and the director has alerted farmers that GAP certification is necessary for many markets already. Personally, I fear the heavy hand of government (doing the bidding of industrial agriculture), expanding certification requirements to include sale of any agricultural product. I think it is vitally important that we gather as much scientific backing as possible to insure AP does not get saddled with unrealistic and absurd requirements that would shut us out of the market place.

I am willing to perform the test and control.  I'd like some suggestions and help. First off, would anyone other than me be interested in the results?  I suspect that a basic aquaponics system will naturally destroy E. coli.  I have nothing to support this hunch, and please don't think I'm suggesting that I know what I'm talking about.  I don't.  But from all the buzz about E. coli and Salmonella, I'm convinced there is no way to positively prevent it's introduction into our aquaponic systems. Minimize, perhaps, but not eliminate.  So why all the argument about how to prevent it? I think it more useful to practice common sense and hygiene, and study instead some vectors of control.  I'd rather trust that deadly germs are constantly dropping out of the air and contaminating my system and my system is capable of defense, than pray and hope I don't kill my family from one dirty little fly, or heaven forbid, a worm that didn't get a vinegar shower.


So, how's this for a start:  four identical barrel systems with gravel media, composting worms, ebb and flow, no fish (don't think it's necesary), heated to 70 deg. F, and growing lettuce.  I can build them all from scratch from identical materials, new water, new gravel, seed each one with equal amounts of existing system gravel to speed up cycling, and run a fishless ammonia cycle until all spikes have settled.  Then, find a feedlot, get some poo, make sure it has E. coli HO157:H7.  System 1) Control, add nothing except ammonia to keep biotics alive, 2) add scoop of poo directly to FT, 3) add scoop of poo to mesh bag with airstone, hang in FT, 4) add scoop of poo to media in GB.  Test daily the water, lettuce, and bioslime from each.  Publish progress.


Any results would not be gospel, of course, but might steer us down a better road than crossing our fingers.  If I do this, I need help with testing, and perhaps a source of E. coli laden poo.  I saw on the Friendly link that Sylvia posted that they have a lab that will test for $35 each.  At 3 tests on 4 tanks per day, that's about $3000 for a week.  I can't absorb that myself. Maybe someone out there has some information on a lab that would volunteer the tests, or we can chip in to pay for it.  Kobus, you're the scientist, any critique here is welcome.  I live in central California.  Maybe Peter Shaw has some connections with the college here for lab-work.  May I call the experiment Shitponics?

I think some experiments are a great idea.


I don't know that testing each day is required. A pre-start up test should be done to make sure the source water and the systems before the inoculation are free of fecal contamination.  Then testing after inoculation to make sure the inoculated systems test positive and got enough of a dose to be of concern.  Then weekly testing to see how long it takes for the levels to drop and probably just testing the water would be sufficient to give an idea of time ranges involved and help show where future testing should be more precise.

You should probably have the systems isolated from each other to some extent and write up some procedures about washing up between contact with any of the test systems.


I would say you probably need two control systems and two dosed systems.  Keep the experiment as basic and simple as possible to start.


You may be able to run some basic tests where you just test for and inoculate with fecal matter and do basic generic e. coli tests which usually cost less and you may even be able to get materials to do some of the testing yourself.


Collecting the test samples will probably be the trickiest part.  e. coli is normally on human skin and part of our digestive system so careful handling of all sample collection equipment and containers will be necessary along with gloves and careful handling of anything connected with the systems since it will be way easy to mess up the experiment just by sticking your hand in the water of any of the systems.


One issue I do see is that most e. coli tests simply test for the presence of generic fecal coli-forms and the less costly or difficult ones don't necessarily tell you how much but simply a positive or negative.  This may mean that most systems will test positive with such tests even if the levels are not high enough to be dangerous.  (put it this way, if you were to swab around most kitchen sinks and run a generic e. coli test, You will likely get positive results seeing as e. coli is on human skin.)

Ok. If only one component were tested, should it be the water? I want the to test the substance most likely to hold the germs, like an anaerobic corner of the growbed, maybe a dipstick tube in the growbed, farthest from the drain. It seems that a generic test would not prove anything, since some E. coli is actually beneficial and lives in our gut (friendly newsletter). I thought to test daily because it may not last a week, and then we'd have to start all over to determine how quickly it is destroyed. This is assuming it even gets destroyed, it may grow and get worse. I agree about cleanliness to avoid cross contamination, but I think the growing environment should replicate common practice, which is anything but sterile. Maybe two controls, one adjacent to the E.coli systems, and one in a HEPA clean room. It would be simplest to test onsite, if possible and accurate. Thanks for the input TC. Where do I get a generic kit, might test my current systems just to see where they read. Anyone ever test there system with a generic kit, and with what results?

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