Modern day slavery

Jessa • Unofficial nomad. Aspiring midwife. Fierce lover of naps.
I just watched a documentary on Netflix called "Food Chains". It basically is talking about where our food comes from (in the USA), mostly our fresh produce. It exposed the harsh conditions the field laborers are having to live with every day. These field workers are basically modern day slaves. They're being paid much less than minimum wage (usually somewhere between $50-$400 a week for 70 hour work weeks), almost all of them live under the poverty level, and they're working an insane number of hours every week.
The problem is that these massive food chains (like Walmart, Kroger and Publix) are keeping their produce prices extremely low, and since they're on the top of the food chain in the produce business, they decide which farmers they will employ, how much they'll pay the farmers for their produce, and what the produce should look like to be "acceptable". The farmers then have no choice but to pay the field laborers very little to meet the demands of the grocery store . According to this documentary, modern day slavery in the food industry exists entirely because of these huge chain stores.
What are your thoughts on modern day slavery? Did you know it exists? Do you have any ideas on how we can make a difference in the lives of these millions of field workers that pick virtually all of our fresh produce?