This is a picture of my great grand-daughter taking her first taste of a strawberry. Was it sour? From the expression on her face, it would appear so.
Things have changed in the way we grow our foods nowadays; back when I was a kid, there was never a 'sour strawberry'; never a berry that didn't taste sweet - juicy, and they were grown organically.
I found this incredible list of foods that are now altered in many ways; the harmful effects on all of us. The article is lengthy; the links are numerous to be sure, but it's well worth the read I think.
Here's the link: http://www.raw-wisdom.com/genetically-modified-food