I have often heard that the quality of food and produce developed in
China is not nearly the quality that it is in the U.S.  Personally,
I've often gotten sick in China from eating produce.  Some say that
it's because of the pesticides they use, so you just have to wash the
produce and fruit really well.  But, I wonder if there is something
more fundamental about their fertilizers (some say they use human
fesces) or anything else that would suggest that there are more
concerns/dangers from eating fruit/produce in China than in other
developed countries.

I'm looking for quality research and/or quality articles that would
provide corroborating evidence on the nature and extent of the dangers
of eating Chinese fruit and produce - and that may explain why those
dangers exist.

Just a free comment.

Eating raw produce, especially unpeeled fruit or vegetables that have
not been thoroughly washed can cause stomach problems in any foreign
area, not just in China.  And yes, fertilizing with "night soil" can
increase the likelihood.

But this does not have to be the source of your experience.  There are
different microbes or strains of microbes in foreign areas.  The
stomach of a traveller that is not accustomed to them will often
rebel, some more than others.  This is definitely not restricted to
China.  Persons who have travelled widely are often less susceptible
to problems, as their stomachs have become accustomed to the greater
variety of microbes.  From experience, they may almost unconsciously
be more selective about what and where they eat.

Hope this helps a bit.