"Vote with your dollars" is a common phrase, meaning support businesses you agree with by buying their products (and vote against other companies by NOT buying theirs).
How well does that work in food products? That is a question Kristy Athens considers in her work, which includes an Oregon Conversation Project event called "Good Food, Bad Food: Agriculture, Ethics and Personal Choice."
She's also vice-president of a farmers' market in Eastern Oregon. visits with details on food purchasing strategies.