As much as I'd love to brain the next deer that's eating under my apple tree I'm also aware that that deer might have been stuffing its face at god knows what dumpster or drinking from the river downstream of town (which has a several hundred year manufacturing history so I wouldn't drink the river water).

Farming animals for meat has its problems but it does impose much stricter controls on the inputs. No farmer raising livestock for human consumption is feeding their animals contaminated food and water if there are other options available. If DuPont is upstream of your farm you're probably SOL but that's the exception not the rule.