Marijn Zandee wrote: Dear Joe,

If I remember the article correctly, the researcher assume this is done by the root growing around the bacteria and then somehow digesting the bacteria. I don't remember there being any mention of bacteria traveling inside the plant. Based on the article I would assume for now that the bacteria are killed and digested in the spot where they are captured.

I don't think so.

From the PLOS paper:

Here, we explored the possibility that plants take up and digest microbes as a source of nutrients. We discovered that Arabidopsis (Arabidopsis thaliana) and tomato (Lycopersicum esculentum) are able to take up non-pathogenic E. coli and S. cerevisiae into root cells, digest and use these microbes as a nutrient source. Our results show that the uptake process involves modification of the walls of root cells which is followed by active incorporation and degradation of the incorporated microbes.

From another recent paper

Phagomixotrophic ingestion of intact microorganisms is widespread amongst algae and endocytosis of prokaryotes is the probable origin of photosynthesis in eukaryotes. Although increasing numbers of plant endophytic microbes have been identified in a range of plant tissues including roots, until recently direct uptake and digestion of microbes by angiosperms for nutritional purposes has been unrecognized. However, it has recently been demonstrated that microbes are acquired by the roots of angiosperms and that their associated N can be used nutritionally by the plants. This discovery represents a potential step change in our understanding of competition for resources between soil microbes and plants, and how N is cycled in the terrestrial biosphere. What is not currently clear is what the quantitative significance of this process is when compared with other routes of plant N acquisition from soil.

Of course, this is not to say that the microbes are viable inside the plant nor that human pathogens can be taken up in this way.

As indicated in the original thread, it would be interesting to hear Ralf's views on what these papers mean, but the implication of what he was saying (by referring to these papers) was that he considered it a risk that plants could take up viable human pathogens from being grown in human faeces.

Dear Joe,

Thanks for starting this poll.

Regarding pathogens moving inside plants. I think you may be referring to this thread: forum.susana.org/forum/categories/17-fer...us?limit=12&start=12
In which Ralf Otterpohl mentioned a very interesting article from PLOS ONE:
www.plosone.org/article/info%3Adoi%2F10....journal.pone.0011915

In the article, researchers, quite convincingly in my opinion, proved that plants can capture and metabolize soil bacteria as a source of nutrients. If I remember the article correctly, the researcher assume this is done by the root growing around the bacteria and then somehow digesting the bacteria. I don't remember there being any mention of bacteria traveling inside the plant. Based on the article I would assume for now that the bacteria are killed and digested in the spot where they are captured. In my eyes this makes it unlikely that a plant could contain many viable bacteria via this pathway.

Regards

Marijn

Well I think it is about risk. The risks of consuming fish swimming in a weak faeces solution must be relatively low, otherwise people would be sick from diarrheal pathogens they caught from eating the fish. I don't ever remember reading that was a measurable pathway for the pathogen infection.

On the other hand, there is a higher risk from eating pathogen-containing faeces which is directly attached to the thing you're eating. Of the thing (insect, lettuce or whatever) has been washed/cooked hygienically, the risks must be considerably lower - although I do remember reading on this forum about the idea of pathogens being able to move up the inside of growing plants.. Again for me I think the benefits of using faeces compost must be weighed against the risks, and I think the risks of growing food which is eaten uncooked in faeces compost are too high.

So cooked insects.. unlikely to be a problem. Insects cooked and then pulverised into fish food, very unlikely to be a problem.

As a "Gammelfleisch" tested German it wouldn't make a big difference I guess (lots of scandals with rotten meat being sold to customers in Germany during the last few years).

But I would probably feel better about it if the insects were not fed alive/directly to the fish, but rather dried or better heat-processed before; Although ultimately it probably doesn't really make a difference...

P.S.: Fertilizing fish-ponds with manure is already a common practice to stimulate algae growth as Tilapia feed. Not exactly the most appetizing thought, but I have eaten such Tilapia (and catfish that feeds on the small Tilapia in the same pond) and it was very tasty.

However, it is sometimes better not to think about it too much

P.P.S.: Knowing the amount of (human & untreated) feces that flows into the very shallow Lake Victoria, I guess most Europeans have eaten fish swimming in somewhat diluted feces before, as the catch is exported on a large scale. Pangasius from the Mekong-delta etc. is probably even worse in that regard.

OK, so what if you knew the faeces had (or was very likely to have) pathogens in it, Krischan? Would you consume the insects and/or the fish then?

Once you have a closer look at industrialized meat production, the idea of eating fish fed with shit-eating insects sounds like a very healthy and organic way of getting animal protein Edit: In fact the more pure the human feces are the better.

Are you bothered if human faeces is involved in the human food chain?

Personally, I'd be a lot more comfortable eating something which ate something which was consuming faeces than eating something which consumed* faeces.

* for this, assume that 'consumption' includes living within or eating other things that are living on the faeces


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