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Friendly Aquaponics
Special Newsletter

Special Edition Newsletter Number 5
October 9th,  2011
Images from our farmily aquaponics farm
Aloha Friend,

Tim and I believe what everyone is doing with aquaponics matters, it is all vitally important, and without conscious, mindful operation of our systems, the food produced can end up being dangerous or possibly even deadly to the people who eat it. We believe we all bear a huge responsibility to not only the people we feed, but the people we teach, and we, as trainers, take this responsibility very seriously.

Based upon emails we've received, there seems to be some confusion in the minds of some who read our last newsletter. Here's our clarification: we are NOT saying that adding earthworms to an aquaponics system is dangerous, or even detrimental. Quite the opposite; earthworms, properly sourced, are a tremendous benefit to aquaponics Systems, and perform an essential role in systems that do not have gammarus.

Our concern is motivated by the actions of one of our students, who recently added a media bed, and then purchased earthworms, castings, and compost combined in a gallon Ziploc bag from an ad on craigslist, and then, unthinkingly, put it directly into his aquaponics system. Earthworms can perform a useful function as mineralizers in aquaponics systems, but the compost that contained the earthworms, in this case, is of an unknown source and composition.

This IS a serious concern; we're not joking or being sensational by saying there's potential danger here: there were 3 deaths and 276 cases in the 2006 California E. coli outbreak which was caused by spinach from a grower who had leased land from an Angus cattle rancher. In May 2011 in Germany, 45 people died out of 3,785 cases of E. coli. This was a different strain: it was H014:H4. Many of those who lived will be on dialysis for the rest of their lives because their kidneys were ruined by the disease. The cost JUST for the sick leave alone for all the affected people was $2,840,000,000. Yes, that's billions, not millions. Just for a moment, imagine you are a relative of one of the dead, or one of the ones who will have to go to dialysis twice a week for the rest of your life. 

You can go either of two ways here: you can assume that a potentially dangerous thing is safe without requiring proof; OR you can assume that a potentially dangerous thing is dangerous until you can PROVE that it's safe. We want to stress that the compost and its potentially dangerous contents are what we fear, not the worms independent of questionable compost.

What we're saying is this: if you are providing food for any human being to eat, you have to beware of all possible contaminants and be prepared to control them. We are welcoming large numbers of new people joining our aquaponics revolution and it is critically important for everyone to understand the invisible microbiological world that surrounds us. Aquaponics is still a new field and could be subject to disastrous consequences if even one person contracts an illness from aquaponically-grown food that was near questionable compost.

Given the confusion in our small but thriving community, I am quoting scientific sources to facilitate a scientific and neutral discussion about the risks and benefits of worms, compost and aquaponics.

While there are certainly other causative agents of of food-borne illnesses, E. Coli and Salmonella pose the most concern for food producers in general (especially leafy-greens producers), given the ease of contamination of the fresh food we grow. Leafy-greens contamination can happen completely independent from any involvement with an aquaponics system. In fact, there is evidence that in our systems, the harmful pathogens are actually crowded out by beneficial bacteria over time (Shereif et al., 1995).

According to the Center for Infectious Disease Research and Policy, there are over 225 different strains of E. coli, the vast majority of which are not in the least harmful to humans, and which are, in fact, critically important to a healthy functioning digestive system (Tannock, 1995). However, some strains have developed excess genetic material that turns a harmless bacterium into one that poses a very dangerous threat to anyone who inadvertently eats even a few of them.


One of the most well-known of these pathogenic bacteria is E. coli O157:H7, a strain that is one of the most virulent to humans, and one which causes hundreds of thousands of illnesses each year, according to the USDA, which also places estimates of the cost to the U.S. economy at millions of dollars each year. (ERS/USDA 2001-E. Coli). The sad fact is that fresh produce has become a very common source of E. coli O157:H7-caused illness since the first outbreaks were reported in 1991, associated with spinach, lettuces, apple cider/juice, cabbage, and sprouts (Rangel et al., 2005). Anyone who is immune-compromised, elderly, or very young is most susceptible to this strain, and ingestion of these bacteria can cause lifelong illness or even death.

Although both cattle and deer are carriers of E. coli O157:H7, it is harmless to them because it doesn't bind to the walls of their gastrointestinal tract. In humans, however, this strain binds to the cells that line our gut, resulting in bloody diarrhea, and in some cases a series of dangerous lifelong complications or even death.

An “outbreak” of illnesses from is defined by the Center for Disease Control as "two or more cases from the same direct cause or source of exposure." (MacDonald and Griffin, 1982).

There were 8,598 cases associated with 350 separate outbreaks reported to CDC in the years 1982 through 2002 of E. coli O157:H7 alone, which accounted for less than one-tenth of 1% of the total number of food-borne illnesses reported during that 20-year period (Rangel et al., 2005). So, to extrapolate out, there was a total of at least 8,598,000 people sickened from food-borne disease reported in that 20-year time period!

Salmonellosis is a bacterial disease caused by the bacterium Salmonella. Many different kinds of Salmonella can make people sick, with symptoms of diarrhea, fever, and stomach pain that starts one to three days after their exposure, and lasts up to a week. Several Salmonella strains have proven to be resistant to antibiotics, and are estimated to infect over 1.4 million Americans each year, with a cost to the U.S. economy of around $3 billion. This means 150,000 people are hospitalized and 600 die from the infection each year. (ERS/USDA 2001-Salmonella) Traceback has shown that many of the Salmonellosis outbreaks were sourced from farming operations, as they have been associated with improper procedures involving meat, poultry, and produce. Much of current food safety legislation has been put in place to protect consumers from these strains, and to educate food producers on good hygienic agricultural practices.

Most Salmonella and pathogenic E. coli infect not only humans, but also domestic animals and many wild animals, some of which become ill, but most of which do not. These asymptomatic carriers shed billions of virulent infective organisms in every ounce of their feces. E. coli O157:H7 can persist for months in untreated animal waste, and Salmonella for up to two years (Winfield and Groisman 2003). Flies caught around farms often carry Salmonella, and shed up to ten million bacteria per dropping, which is enough to cause disease in an otherwise healthy adult male, thus it is critical to prevent flies from being attracted to your aquaponics system.

Proper composting of animal wastes on an integrated farm is an important step for reducing or eliminating Salmonella and E. coli contamination, and to break the cycle of reinfection. Our student has no way of knowing if the compost he put into his system was treated, or if it contained untreated contained animal waste, and/or if the animal waste was contaminated.


Animal and human wastes can be concentrated carriers of both these potentially deadly pathogens, so it is crucial to prevent the introduction of these pathogens into aquaponics systems through the addition of compost containing earthworms unless you are absolutely certain the compost material they came from is free from these pathogens.

The accepted methods of ensuring this are to maintain the temperature of composting animal waste at 160-170°F for a minimum of 21 days to kill these pathogens, but this would obviously also kill the earthworms. Aging combined with manual turning of compost increases aeration and raises the pH, which seems to reduce both Salmonella and E. coli (Kuo et al., 2004), but the aging requirement, according to accepted food safety and organic certification standards, is 120 days minimum. Interestingly, research also suggests that vermicomposting (composting using earthworms) actually eliminates both Salmonella and E. coli from animal wastes (Kumar and Sukaran 2005), although the method of this elimination is not yet understood. This study shows that these pathogens were not measurable after going through the gastrointestinal tract of earthworms.

Education of the food producers on the issue of microbiological safety is critically important. Proper hygiene (Simonne, et al. 2005) and certified testing are inexpensive ways to prevent the spread of these harmful bacteria, and to be certain that anything you put into your system is safe. A microbial test sent to our local lab costs $35 to test for Salmonella, Generic E. Coli, and E. coli O157:H7. From what we can tell, our student introduced something potentially lethal, with no consideration of the dangers involved. Know what you're putting into your system, always.

Thank you for taking the time to read this and find out more about it. It's something we have to live with, just like freeways. But, just as no one in their right mind tries to walk across a freeway (they use the pedestrian overpass); there are ways to deal with this situation that allow for the maximum safety and health for everyone involved.

References and Further Information

Shereif, M.M., Easa M. El-S., El-Samra, M.I., and Mancy, K.H. 1996 A Demonstration of Wastewater Treatment for Reuse Applications In Fish Production and Irrigation in Suez, Egypt. Wat. Sci. Tech. Vol 32, No. 11, pp 137-144, 1995.

Tannock, G.W. Normal Microflora, Chapman & Hall, 1995.

ERS/USDA. 2001-E. coli. Economics of foodborne disease: E. coli.

Rangel, J. M., P. H. Sparling, C. Crowe, P. M. Griffin, and D. L. Swerdlow. 2005. Epidemiology of Escherichia coli O157:H7 outbreaks, United States, 1982-2002. Emerg Infect Dis 11:603-9.

MacDonald, K.L., Griffin, P.M., Foodborne Disease Outbreaks, Annual Summary, 1982, Enteric Diseases Branch Division of Bacterial Diseases Center for Infectious Diseases.

ERS/USDA. 2001-Salmonella. Economics of foodborne disease: Salmonella.

Winfield, M. D., and E. A. Groisman. 2003. Role of non-host environments in the lifestyles of Salmonella and Escherichia coli. Appl Environ Microbiol 69:3687-3694.

Kuo, S., Ortiz-Escobar, M.E., Hue, N.V., and Hummel, R.L., 2004. Composing and Compost Utilization for Agronomic and Container Crops,

Kumar, A. G., and G. Sekaran. 2005. Enteric pathogen modification by anaecic earthworm, Lampito mauritii. Journal of Applied Sciences and Environmental Management. 9:15-17

Simonne A., J. Brecht, S. Sargent, M. Ritenour, and K. R. Schneider. 2005. Good Worker Health and Hygiene Practices: Training Manual for Produce Handlers. UF/IFAS EDIS Fact Sheet FCS8769.


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Free Farm Tours
Aquaponics tour at the Friendly farm!

We hold a free workshop on our farm the FIRST Saturday of every month,  focused on growing food with aquaponics and permaculture.  Click here for information. See you there!

If you are a school, a non-profit organization, an organization working with the poor, Native Hawaiians, or ex-inmates, or if you are a church, we will hold a free farm tour for you anytime. You DO need to email us first to schedule, or we might be out on errands!


3-1/2 pound kalo (taro root) grown in a 2" net pot (little bump at bottom)


4-month old prawn (macrobrachium rosenbergii) grown in hydroponics troughs of our aquaponics systems

Special Offer! Sign up for our October 2011 Hawaii Aquaponics Training now, and we will email you our Micro System package so you can begin studying aquaponics!

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In The Farmily

It was Christmas Eve, 1979, in  Kawaihae harbor on the Big Island of Hawaii. I had been fishing my 56-foot sailing fishing boat "Tropic Bird" out of Kawaihae for about a year after launching her in 1978. My crew and I had finished hauling our shrimp traps about ten miles offshore, iced our catch down, and headed back to the dock about 4 in the afternoon. We got the boat tied to the dock about 5:30, and offloaded our catch to an eagerly waiting buyer. Now it was time to  enjoy a beer in Hawaii, and watch a magnificent sunset over the Pacific Ocean.

My crewman had a beer with me on the dock and then headed home to his family. There I was, celebrating Christmas eve all by myself.

I wasn't feeling lonely or sad, in fact, as it got darker and the masterpiece sunset wound down, I was appreciating the peaceful whispering of the nighttime wind in the harbor, the stars twinkling overhead, and the sound of the little waves lapping against the hull of my boat. Just then, some running lights appeared at the harbor entrance, signifying that a boat was coming into the harbor.

I recognized the boat right away, and knew the crew; friends of mine, they worked another boat based out of Kawaihae harbor. It was a 65-foot tugboat that was working with the local OTEC (Ocean Thermal Energy Conversion project) as a supply boat, and soon its crew was tying it up to the dock just in front of Tropic Bird.

We got the hibachi and the folding lawn chairs out on the dock, drank some more beer, and cooked dinner together. We ate, drank, and yarned tall fish stories and sea stories into the night. Somewhere along the way I got out my Hoyt Axton tape and played it on the little cassette player we were using for a sound system.

Discussion ensued, my friends REALLY liked the Hoyt Axton tape, and I really liked another tape they had brought to the party. I'm not sure what happened next, but I ended up facing the 110-pound, 5-foot 4-inch tall girlfriend of one of the tugboat crewmen at the edge of the dock.

We apparently had made a bet that whoever could throw the other person off the dock into the harbor would win the other's tape.

After four beers, I vaguely remember saying something like "No girl is gonna throw me off no dock!". Now, the problem with this is that they had adopted a sneaky but effective tactic; if either of the guys had been their champion, I would have no-holds-barred wrestled him off the dock and into the water. But what body part do you grab a girl by if she's your friend's girlfriend?

So, severely hampered by ethical and moral considerations, I began the match. I did my best to maneuver her to the edge of the dock without grabbing any forbidden flash, and she did everything but kick me in the family jewels. We got to the edge of the dock, I got ready to throw her in, and she reached up and bit my chin as hard as she could, drawing blood.

I was so surprised by this that I lost my balance and we both went in the water. We swam over to the boarding ladder on Tropic Bird, got out of the water, and dried off. I decided the tape should be theirs because of the brilliant tactics their champion had used.

They reciprocated and gave me the nice tape of theirs that I'd liked, so, except for the new bloody welt on my chin, I felt all was well with my world. Christmas eve, 1979, in Hawaii. Nothing wrong with that.

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This email, our manuals and construction plans are all copyrighted by  Friendly Aquaponics, Inc, Susanne Friend and Tim Mann, 2008-2011

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PO Box 1196
Honoka'a, Hawaii 96727

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