E-coli Spinach from Human Manure?

I was thinking about the whole e-coli spinach deal and then thought back to a conversation I once had with my friend Karen, who is a science/environment writer, regarding the EPA's rules on fertilizer.

As of right now they still haven't found the source of the e-coli contamination of the spinach. But what if the government or certain corporations actually know the source but don't want to divulge it because it would harm certain corporate profits from the manufacture of fertilizer.

What if it is actually the fertilizer that is causing the contamination?

Namely, what if it is fertilizer that is derived from human waste that is causing the contamination? Fertilizer which the EPA has recently loosened restrictions on (as part of the 2002 Clean Water Act, ironically) and is now widely used.

Think about the implications. The EPA, the BUSH EPA, approves the use of HUMAN WASTE to be sprayed on our food supply and now food is turning up mysteriously full of e-coli. Not to be a conspiracy nut but...