Don't be absurd. There are dozens of wheat pathogens alone (here's my favorite: https://en.wikipedia.org/wiki/Stem_rust ) and we as a civilization have been dealing with them for a long long time.
Indeed, read a infectious disease news collection source like http://promedmail.org/ long enough and you might be surprised we have anything to eat beyond Soylent Green. Everything you love to eat has a host of pathogens that want to eat it first.
Try gardening/farming. Starting with eggs. Snakes, weasels, raccoons, even the hens want them. Hawks want my chicks, as do snakes, raccoons, weasels, foxes, bobcats, and coyotes. Weasels, coyotes, foxes want the pullets and adult hens. Its like anything I want to raise is a buffet for nature. On the other hand, I have an electric fence.
So many people have stopped their small scale chicken raising/egg production, like one family I know, after they learned "fox in the hen-house" isn't just a turn of phrase.
Both my parents grew up on farms, and we kept a big garden when I was growing up, so I know this very well, although reading the article that link collects for many months was serious sobering.