When frogs, catapillars and such show up in produce that is not such an odd thing. After all, we grow where they live. Problem is how the food is handled...or not handled. Improper washing and such. That would be the first clue of where not to eat. I have been in food and beverage most of my life and owned two restaurants. The health department loved me because my facilities were so very clean. I watched everything, but not every restaurant is that particular with how their food is handled.
To know how the Chinese really eat, go here and have a look at these photos. You may never want Chinese food again, though.
http://knuttz.net/hosted_pages/China-Food-20070124