About 550 million chicken eggs have been recalled because of potential contamination with Salmonella enteritidis, and reports of associated illness have climbed dramatically in recent months, according to the CDC. Federal, state and local public health officials have traced the reported illnesses back to eggs produced by two Iowa farming operations, but Jeff Farrar, the FDA's associate commissioner for food protection, said during an Aug. 23 media briefing that since mid-May, the two companies have shipped eggs to wholesalers, distribution centers and food service companies in more than 20 states.