I'm very concerned that e coli is being under evaluated as a potential containment.  Repeatedly I'm finding references to the idea that e coli cannot exist in aquaponics, but the references are circular and based on statements without substantive scientific backing, and I beg to differ. While there is evidence that e coli isn't a normal aquaponic component, the potential for cross contamination is still high, and according to University of HI, http://www.ctahr.hawaii.edu/oc/freepubs/pdf/FST-38.pdf (link isn't working right, help appreciated) there is still a potential for the organism to exist in an aquaponic system, although with competition for space with the positive bacterial it's ability to over-run a well maintained system seems to be limited.  If this particular concern is better addressed in a more complete study please direct me to it!  If aquaponics is to be proven safe, regular testing must occur in order to prove that this contaminant isn't in the system.  The tests are expensive, and require a UV light to guage the presence of e coli (with most the tests I've looked at). Is anyone currently testing for e coli?  Can anyone refrence a stronger scientific study for me?

Views: 408

Reply to This

Replies to This Discussion

Hi all,

 

I have an aquaponic system that has been set up for a little over a month in our efficiency apartment and we are getting ready to harvest our first crop of lettuce - it also won't be too long before the basil, cilantro, and other herbs can part with some leaves.

 

That being said - we have an aquatic turtle in the tank. My wife is concerned about salmonella poisoning from eating the plants. I have consistently reiterated that as long as we wash the lettuce, etc. we'll be fine.

 

Is there anyone with experience with aquatic turtles or other salmonella harboring aquatic animals that can help me reassure my wife that we have nothing to worry about? Is there a concern other than basic hygiene that we should be concerned about?

 

Cheers and thanks!

 

Jake

Well, I might be a bit concerned about salmonella and the turtle.  I wonder if there are any tests some one can run to see if salmonella is present.

 

I know that e coli (the forms that we all carry in our bodies) are constantly present and really only become dangerous if they get out of control or into the wrong parts of our bodies.  Because we all provide a vector for introducing e. coli into our systems it is a concern to figure out if some mechanism related to aquaponics can naturally keep the numbers within safe limits without going overboard on trying to control or eliminate it by other means.

 

Salmonella is a bit different.

 

I am not certain that lettuce is a good choice for growing in a system with a likely salmonella carrier.  Lettuce takes up large amounts of water and if you are not cooking it, no amount of washing will get rid of bacteria that is hiding inside the veins and tissues of a plant.

 

I would probably look into testing some turtle waste or water heavily contaminated with some turtle waste to see if there is salmonella present.  If there isn't, I don't think a pet that has no access to the outside world or other possible carrier animals is likely to spontaneously become a carrier.

I found this test...http://www.geneq.com/catalog/en/sas_salmonella_test.html# and have requested a quote from the company.  This appears to meet the requirements needed (quick test, easy read), now we'll find out if it's cost prohibitive.  After reading about the potential for contamination from turtles, I'd flatly advise not to eat the food until testing is done.  In this case (re:salmonella), contaminated water can directly contaminate the food, and cross contamination due to poor hygiene after simply handling turtles has led to food borne illness outbreaks.  This is high risk, and should be treated as such.

I found another test on the same discussion http://www.exit15.com/instant-food-test-strip-kit-for-salmonella-an... this tests for both salmonella and e coli, but it's not cheap ($10/test).  That's a lot less expensive than a hospital stay, or worse...

Daniel E Brown said:

I found this test...http://www.geneq.com/catalog/en/sas_salmonella_test.html# and have requested a quote from the company.  This appears to meet the requirements needed (quick test, easy read), now we'll find out if it's cost prohibitive.  After reading about the potential for contamination from turtles, I'd flatly advise not to eat the food until testing is done.  In this case (re:salmonella), contaminated water can directly contaminate the food, and cross contamination due to poor hygiene after simply handling turtles has led to food borne illness outbreaks.  This is high risk, and should be treated as such.

My only concern is which Salmonella and E. coli are they testing for.  E. coli is the most common organism in our gut.  When they test water for E coli they are not testing for the E coli H7:O157 they are testing for the common gut organism.  This is a sign of fecal contamination and therfore the possibility of pathogenic organisms may exist.  These tests are expensive and have no controls with them so you wouldn't even know if they are working properly.  They might make you feel better if they were neg but that is not proof of the presence of an pathogenic organism.  Before you believe these tests alone my advise as a Medical Laboratory Scientest is to research these organisms and how to test for them.  I have no idea wether a turtle would contaminate your food.  Not all turtles are infected with Salmonella.  As a kid I played with turtles all the time and did not wash my hands that often and I never got sick.  Just make sure you know what the tests are testing for or you have wasted your money.  For a Clinical Laboratory to prove that the organsim is E coli H7:O157 costs a lot of bucks.  It is no easy chore. 
While testing for the specific E coli H7:0157 might be prohibitive, I don't think I would recommend people eat large quantities of any other e. coli strain.  Even the e. coli that most of us have in our guts at all times will make most people sick if you get enough of them into the wrong part of your body.  (Ladies just think of a urinary tract infection or bladder infection, those are normally caused by the e coli from your own gut managing to get into the urinary tract in great enough numbers to cause the infection.)  Just because an infection from the lesser strains is rarely deadly, doesn't mean they won't cause sickness.  So, if the test is positive for E. Coli beyond safe levels, I wouldn't advise eating lots of raw food from it or feeding food from it to anyone with a weak immune system.

 Hi everyone I apologise for my wrong information about E coli  I stated the strain wrong.  It is E coli O157:H7 not the oposite. I was trying to multitask by doing labwork and typing this.  Studies have shown what multitasking does for your brain.  I just prove it.  Sorry Look before you speak. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

e

Thanks for all the answers re:aquatic turtles & e coli

 

I have been reading up on this for a few days as well as eating the lettuce leaves for the past week rendering no ill effects thus far. I have read that older, healthy, non-stressed animals typically release less bacteria (if any). The turtle is over 6 years old, healthy, and virtually stress-free (she is well-fed Mississippi Map Turtle, has an ~8" carapace, and I frequently catch her frolicking playfully with the fish). That being said I will likely not be serving the produce rendered from this particular set-up to anyone else but myself. But man she sure fertilizes those plants. :)

 

Although the strain aquatic turtles typically carry is not the frequently cited and feared O157:H7 serotype (found in cattle) the Pomona and Salmonella subtype I serotypes in aquatic turtles appear to be just as nasty - particularly for children. I'll let you all know how well the potential salmonella serotype fairs with a healthy 28 year-old.

 

If anyone else is looking for more detailed information about the Salmonella in aquatic turtles I found this CDC report from 2007 "Turtle-Associated Salmonellosis in Humans"

 

 

O157:H7 is a type of e. coli generally associated with feed lot beef and the waste from such feed lots (since feed lots tend to use lots of antibiotics to keep animals from falling sick in such crowded conditions and eating grain the waste from such facilities are likely to contain large amounts of antibiotic resistant bacteria.)

 

Just because turtles can carry salmonella, it doesn't mean they all carry it does it?  There are many wild animals known to be likely carriers of salmonella (after working as a technician on a show with lots of animals and probably half of them could carry salmonella, everyone used the hand sanitizer often.)

 

I believe there are a few test kits you could get to see if your turtle is a carrier by checking the wastes with a test strip.

 

 


Last years FDA recall of spinach was caused by E coli 0157:h7. The Ecoli 0157:h7 bacteria was actually in the spines of the plants not cross contaminated. This was caused by the plants up take of the bacteria from the ground water. Ecoli 0157:h7 does not live in the intestinal tracts of fish but could be put into the system by cross contamination. Ecoli 0157:h7 lives in the intestinal tracts of warm blooded animals. In the HACCP plan for the commercial system, I’m building requires the addition of only aged municipal water to remove chlorine. No organic materials can be used in the system from warm blooded animals (manure). If organic fertilizer is not composted correctly it is the perfect source for this particular strain of Ecoli (0157:h7). The cost of testing is about $50 per test needs to be sent to the lab but  this only shows the bacteria is not in the testing sample, ask any meat plant. You can test a sample but that does not mean it is not in the system, just not in the sample. The best method of protection is to keep it out of the system from cross contamination. By the way Chicken poop is used in china and other locations to create an algae bloom to feed the fish in pond raised tilapia, a perfect source for salmonella cross contamination if not correctly composted.


Sylvia Bernstein said:
Dan, I suspect this was started by my blog post today, c'est vrai? I was basing what I said largely on what Kobus just pointed out - that E.coli can't live within the gut systems of fish, and that there have been no reported cases of E.coli from an AP system's produce. I also am not a trained chef, but it seems to me that just about anything can happen with you start introducing outside sources of harmful bacteria, i.e. cross-contamination. I know that some of the problems with the E.coli contamination was from the field workers hands, but wasn't the problem in at least one case also that there was splash-up from rain of manure that wasn't completely composted? If I'm wrong I'm happy to go into the blog post and change this. What are your thoughts?

You might get a negative, if the turtles weren't shedding the bacteria at the time of test, this will not guarantee the absence of salmonella.  If you're dealing with an acknowledged vector (and according to what I've found, many studied cases had a reptile vector, with higher percentage for children).

 

"Salmonella illness remains a major public health problem in the United States, with an estimated 1.4 million nontyphoidal human Salmonella infections occurring annually, resulting in approximately 15,000 hospitalizations and 400 deaths (5). Reptiles are a well-established source of human salmonellosis; a study conducted during 1996--1997 attributed an estimated 6% of all human, laboratory-confirmed, sporadic Salmonella infections in the United States (and 11% of infections among persons aged <21 years) to contact with reptiles and amphibians (6). The epidemiologic and laboratory findings from the investigations described in this report demonstrate that turtles were the likely source of infection in these human salmonellosis cases. Exposure to turtles was associated with salmonellosis, and identical PFGE Salmonella strains were isolated from samples from patients and their turtles in three separate instances. Nontyphoidal human Salmonella illnesses in the United States are common and usually sporadic; therefore, many cases of turtle-associated human salmonellosis likely occur without detection or without a recognized link to exposure to turtles."

 

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5626a1.htm

TCLynx said:

O157:H7 is a type of e. coli generally associated with feed lot beef and the waste from such feed lots (since feed lots tend to use lots of antibiotics to keep animals from falling sick in such crowded conditions and eating grain the waste from such facilities are likely to contain large amounts of antibiotic resistant bacteria.)

 

Just because turtles can carry salmonella, it doesn't mean they all carry it does it?  There are many wild animals known to be likely carriers of salmonella (after working as a technician on a show with lots of animals and probably half of them could carry salmonella, everyone used the hand sanitizer often.)

 

I believe there are a few test kits you could get to see if your turtle is a carrier by checking the wastes with a test strip.

 

 

Good Link there Dan.  Definitely reason to wash well after handling pet turtles or anything from their aquarium and I would probably convert the turtle system to growing ornamental plants rather than salad.

 

Earl, I had long ago read some stuff that said lettuce could suck up water containing bacteria but had not yet run across the info about the Spinach having the e. coli inside.  Good info to know.  Very important to properly compost all manure before applying it to planting beds.  Proper composting not only makes it safer but makes the nutrients a better steady slow release fertilizer that is less likely to burn or cause uneven growth.

 

Yes, in Asia they often use manure to cause algae blooms in aquaculture heck, I've read where they will simply place the privy over the pond and use human excrement.  Luckily most people cook freshwater fish before eating it which is probably why this practice hasn't caused too much illness. 

 

But when we start talking about aquaponics where we love to grow lettuce and other things that we normally eat raw!!!!  It becomes important to keep the warm blooded manure (mammal and bird) as well as avoiding reptile waste in the aquaponics systems. 

Reply to Discussion

RSS

© 2014   Created by Sylvia Bernstein.   Powered by

Badges  |  Report an Issue  |  Terms of Service