You can't. So... abstain from everything? Make everything yourself - how will you have time with a job? Will you know the food you grow is safe and that your ground isn't polluted with things you can't test for at home? How about the equipment used to make that food - is the metal in that plow made of lead? Is the engine on the tractor safe?
Your due diligence is only possible because other people - usually with specialized education and/or experience - have made laws and standards to keep you safe. You don't have to personally check everything.