While I would like to live in a pure world with pure water and pure air and pure food I know that I don't and can't. The breath I just took has pollutants not only from around where I live but, at least microparticles, of pollutants from all over the world. The water I drink is processed and has so many chemicals added to "make it safe" that the creator would have a hard time identifying it as water at all. From my first shiny candy coated peanut as a child to the crisp, juicy, shiny red apple I ate last night I have been eating car wax on pretty much a daily basis (Carnauba is used as a food glaze and wax).
The fact is that we try to provide safe food for our families and our animals. We all do the best we can and for the most part what we are able to get and use as food/feed is safe, treated but safe for us and our animals to eat. Short of a very expensive totally verifiable organic diet it is what is available and what we can afford. Sure I could feed my animals raw animal protein but stop for a moment and think what is in that "fresh" meat. What started out as a healthy "organic" calf grew to be a scientifically manipulated and highly marketable chunk of edible protein.
The point I am trying to make is that whether it is Purina Chicken Feed or 500 dollar an ounce Truffles from Gelson's in Beverly Hills there is no such thing as "pure" food and has not been for a long time. UNLESS you grow it yourself, control its diet, use only purified water to irrigate your garden which you have in a greenhouse with air purifiers, etc., etc., etc.