water borne diseases

[Jack Dunbar]

Is there a simple and/or inexpensive tests for things like coliform, ecoli etc? what are some of the safeguards that we can do to limit the possibility of introducing these? I hear of a lot of people that may want to add supplements to their FT/GB but what about toxicity? 

[Anne Phillip]

Hi Jack,

I have looked into this here in Portland, OR. I can have samples of my water or leaves tested at a food safety lab for E. coli O157:H7 and Salmonella spp. but the tests aren't cheap. They are about $30 each (approximately, I don't have my notes on me right now). Since fish are poikilothermic ("cold-blooded"), their enteric bacteria wouldn't be the source of the E.coli, although freshwater fish may have some other pathogens of concern. But since people are interacting with the system, there is always a potential for introduction of E.coli. At the very least, this means there should be best practices about working with the aquaponic system (wash hands before) and harvest (don't touch any water or biofilm and then touch your plants). Beyond that, we should all be pushing for more research into the food safety of aquaponic systems versus other soil-based methods. I have found a couple of papers, included at the end of this message, but we need to have a good body of research to back up the safety of aquaponic systems. Until then, it may be a good idea to test batches of your produce for E.coli and salmonella so that you have a documented chain of evidence as to the food safety of your produce. It isn't required by any means, but it isn't currently required of soil-based farmers either. The idea is that by including best practices, you can ensure that if there ever is any question about the safety of your produce, you can document that it has been safe and that your produce was not the source of any problem. I would love to hear from others here on this forum about other sources of research documenting food safety or other best practices that can be implemented. Also, it is a great idea to have your aquaponic system contained, either indoors or in a greenhouse, so that there is no possibility of contamination from warm-blooded animals like birds, raccoons, or deer. And, all of the water you use in your system, either to start the system or add replacement water, should be from a potable source. Possibility of contamination increases when you use a surface water source for your water.

Here are a couple of research articles I have found on the subject: 

A Preliminary Study of Microbial Water Quality Related to Food Safety in Recirculating Aquaponic Fish and Vegetable Production Systems      

http://4aghawaii.org/files/69001957.pdf

On-Farm Food Safety: Aquaponics (This elaborates on best practices)

http://scholarspace.manoa.hawaii.edu/bitstream/handle/10125/13450/F...

Aquaponics and Food Safety (overview and more best practices)

http://www.byap.backyardmagazines.com/Travis/Aquaponics-and-Food-Sa...

Food Safety Study of Leafy Greens Irrigated with Tilapia Farm Effluents (compares AP with soil-based lettuce in terms of microbial contamination- mentions UV as a possible method of treatment, but does not elaborate on the UV mechanism)

http://aquafishcrsp.oregonstate.edu/UA/Documents/Reports/Investigat...

I am interested to hear what others have found with regard to food safety and aquaponics!

Thank you Jack for starting this conversation!

[Jack Dunbar]

Hi Anne, I clicked on the articles that you posted and found some very useful information. I hope everybody takes the time to read these articles. Thank you so very much. I hope your weather in Oregon is getting warmer. I still have small piles of snow here and there but our days now are in the low 50's. I have spring fever badly... Take care...

[Anne Phillip]

Hi Jack, I'm glad that you found the articles useful! It is a beautiful day here in Oregon, sunny and getting warmer. I hope you have some spring weather soon! Take care and good luck with everything you're working on.