About 40 businesses and organizations gave their support to BPI in Saturday's rally.
Some of the big names were Wells Blue Bunny, the City of Sioux City, and it's neighbors to the north and south.
A group BPI says they couldn't have done it without, though, was Hy-Vee.
The company provided condiments for the thousands of burgers served at the picnic. Plus, at the last minute, they brought in 14 grills from Hy-Vee stores across the tri-state area.
Officials with the company say they were happy to help out.
"They have a great product that's 100% beef. And it is guaranteed a quality product, and it's guaranteed safe. That's why we're here, we are here to support them," said Tom Daschel, the store director of the Hamilton Hy-Vee in Sioux City.
Hy-Vee originally pulled ground beef that contained LFTB off their shelves. But after community outcry, decided to label it instead and give customers a choice.
You can now pick up ground beef, both with and without LFTB at their stores.