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.

FDA escalates Costco egg recall to Class I, its highest risk level, over salmonella concerns. Learn what Class I means, how recalls escalate, and what it means for you.

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