Follow CBSDFW.COM: Facebook | Twitter

NEW YORK (CBSDFW.COM/AP) — Whole Foods is under heavy selling pressure this week after receiving a letter from the Food and Drug Administration about unsanitary conditions at one of its plants.

READ MORE: US Supreme Court To Consider Controversial Texas Abortion Law

The FDA sent the company a warning letter dated June 8 about conditions at a Everett, Massachusetts plant where food products may have been contaminated with “filth or rendered injurious to health.” The long list of issues included the presence of Listeria. The FDA also said the company’s written response to the conditions was not adequate.

The Austin-based company said that it already corrected the issues and that those steps were not reflected in the FDA’s follow-up letter.

READ MORE: Texas Mother And Son Arrested In Wyoming For Murder In Oklahoma

Shares are down 1 percent in premarket trading Thursday, and down 10 percent this week.

The warning comes as Whole Foods faces growing competition from traditional grocers and big box retailers that have expanded their organic and natural food sections. Last month Whole Foods reported that sales at established stores fell 3 percent during the quarter ended April 10. That marked the third straight quarterly decline.

MORE NEWS: Southlake Ranks 20th 'Best Small City In America'; Keller & Flower Mound Most Affordable

(©2016 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)