Nearly a month after a five-state recall of eggs sold at Costco, the FDA now says consumption of the recalled eggs could "cause serious adverse health consequences or death."

In November, Costco recalled nearly 260,000 eggs sold under the Kirkland Signature brand in 25 stores nationwide. The eggs landed on shelves in Alabama, North Carolina, Georgia, South Carolina and Tennessee starting Nov. 22, according to the company.

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.