Testing the difference b/n organic and conventional crops...and A/P

[Converse]

I just ran across an interesting bit of information for some of you to consider or comment on. It is on the Rodale Institute website. If you go to http://www.rodaleinstitute.org/20110303_yes-there-is-a-difference-b... you can read a short article on testing lettuce crops for nitrogen content. By doing so, it can be revealed if a crop is grown organically or not....but if you continue reading down to the comments...someone adds the info that false positives in testing can come up in certain situations...one of them involves algae...and I was wondering if any of you have the time to read this...do you think this could be a challenge for AP growers in their pursuit of Organic certification?

- Converse

[George T]

Does anyone test the vegetables for nitrogen source, presence of pesticides, etc?  Even if they did, I wouldn't think the leaves or fruits would have algae on them but possibly the roots would.  Hard to believe this would be a problem.