Like "I use 3 groceries - 1 national and 2 local - that I trust to select clean organic products. They all carry some non-organic items and label them as such. I've found all are willing to check when I'm unsure. I've stopped buying corn at my favorite roadside stand because, despite assuring me that the corn was non-GMO, she got an odd expression on her face when I mentioned my allergies. When I got sick after eating it (belly ache) I decided the look and the allergy discussion may have been related and the product misrepresented. Some of this comes as we learn through our mistakes. Other information requires reading and questioning the meat man or the produce manager. I recheck the lists of good and bad every few months to be sure I'm still on track. For example, I buy avocadoes at Costco by the mesh bag (NOT organic) cause I'm going to peel them anyway. I was surprised to find asparagus on the list that is ok to eat non-organic, cause usually it's the things that you peel that are ok. "