Choose Non-GMO Products
At the very least (if you can't find organic), do your best to buy products which are Non-GMO. Products which are Genetically Modified are almost certain to have been sprayed with toxic chemicals which inevitably you ingest.
We've talked about the dangers of pesticides in your food already, but to reiterate--pesticides in your food can cause things like:
Cancer, Alzheimer's, Dementia, Type II Diabetes
Parkinson's, Autism, Allergies, and more.