The Oregon Potato Co. first issued a recall of its IQF Blueberries on Feb. 12, but the FDA on Tuesday upgraded that recall to a "Class I," which, according to the agency, means there is a "reasonable probability that the use of or exposure to a violative product will cause serious adverse health consequences or death."

The frozen fruits were sold in 30-pound cases and 1,400-pound totes and are packaged in polyethylene bags or liners within the totes.

These blueberries were not sold directly to consumers from retail stores but were distributed in Michigan, Oregon, Washington, Wisconsin and Canada. The FDA did not specify where the blueberries were sold or how consumers may have come into contact with them.

The U.S. Department of Health and Human Services, which oversees the FDA, and Oregon Potato Co. did not immediately respond to NBC News requests for comment.

The products were potentially contaminated with Listeria monocytogenes, according to the FDA announcement.