Hmm - may have at least partially answered my own question when I looked back at the article from Sally's link...
"Washing fruits and vegetables with soap, detergent, or commercial produce wash is not recommended. Produce is porous. Soap and household detergents can be absorbed by fruits and vegetables, despite thorough rinsing, and can make you sick. Also, the safety of the residues of commercial produce washes is not known and their effectiveness has not been tested."
