The Food and Drug Administration (FDA) has issued a new warning about thousands of recalled eggs sold at Costco (COST) stores due to potential contamination with salmonella, a bacterium that can cause serious infections. The recall has been elevated to the FDA’s highest risk level.

The FDA has classified its recall of eggs sold under Costco's Kirkland brand as a Class I recall, a designation reserved for instances of the highest potential health risk — including death.

The FDA recently escalated the recall of organic, pasture-raised eggs sold at Costco, reclassifying it to the highest risk category.