Workers at a flagship Whole Foods Market in Philadelphia, Pennsylvania voted to unionize and become the first union in the grocery chain's history.

Now, a battle lies ahead when working out the first contract between Whole Foods and the unionized workers. "This is going to be the longest uphill battle of our lives, but this is not just for us. This is for the people who come behind us and for the people who have been here," said Khy Adams, a Whole Foods employee.

A majority of workers at a flagship Whole Foods store in Philadelphia, Pennsylvania voted to unionize on Monday, becoming the first in the Amazon-owned grocery chain to snatch a labor victory.

The Amazon-owned grocery store brand says it's 'disappointed' in the employees' plan to join the United Food and Commercial Workers union.

Austin-based Whole Foods, which is owned by Amazon, is the latest grocery chain to contend with unionization after workers in Philly voted in favor.