Mail-order health-food giant Daily Harvest identified the ingredient that made nearly 500 customers sick in a massive foodborne illness outbreak.

In a letter to customers updating them on the outbreak, Daily Harvest CEO Rachel Drori wrote the company “identified tara flour as the cause of the issue.”

She wrote the company was no longer using this ingredient, and said it was only used in the French Lentil & Leek Crumbles that were at the center of the outbreak.

Drori wrote that it was the first and only time the company had used tara flour (and likely the last). The company will continue working with the FDA and the supplier to determine the specifics of what in the flour made people so sick.

As the details continue to emerge, the legal issues continue to build.

Bill Marler, a lawyer who focuses on food safety cases, said more than 350 people have retained his law firm and more than 300 of those suffered liver damage. Of those, 100 were hospitalized and 32 had their gallbladders removed.

“Many are still suffering liver complications and the strain of medical bills,” Marler wrote on Twitter.

The outbreak remains one to watch for impacts on the broader mail-order food industry, which has, until now, not seen a major illness outbreak like this.